Kết tủa điện hoá hợp kim w co lên nền thép trong dung dịch nước để chế tạo và phục hồi chi tiết máy bền nhiệt ăn mòn mài mòn

Nghien aril ma hop kim theo huOng thay doi thanh phan dung dich ma them cac chat pall co, vo co lam tang tinh nang qu9 cua ldp ma hop kim, ding vdi thanh phan dung dich ma cac tac gia co

Ten de tai:

"KET TiJA DIEN HOA HOP KIM W — Co LEN NEN THEP TRONG DUNG DICH NU'dC DE CHE TAO VA PHIJC HOI CAC CHI TIET MAY

BEN NHIET, AN MON, MAI MON"

Chu nhi'em de tai: KS Bui Trong Tai Vien KTND & BVMT

Thanh vien de tai: ThS Tr'An Dinh Hien

ThS Bui Trong Tudn

Cd quan thtic hien: Vien Icy thu4t Nhiet ddi & Bic) ve Mei truldng Tp HCM

Cd quan quan IS,: Sac Khoa hoc va Cong nghe Tp HCM

Thdi gian thlic hien: Tit 01/2004 den 06/2006

§ MCC L UC §

Phan A: TONG QUAN

Phan B: THUC NGHIEM

III Nghien catz anh lizOng cag thank plzein dung dich, the (10 ma

3.1 Anh httang cua sit thay doi nOng do Na2W04 den % W trong

hop kim

3.2 Anh hunng ciia mat dO dOng den thanh pha'n hop kim

3.3 Anh huang cua nhiet dO ma den trang thai 136 mat, 18 x6p va

kha nang barn dinh

3.4 Xac dinh kha nang phan 136 cila dung dich ma trong hop kim

W-Co

4.1 Anh twang ciia chedO ram nhiet len dO cdng lOp ma

4.2 Danl.' gia kha nang bac) ve chOng an mon cila lOp ma hop kim

4.3 This nghiem kha nang bao ve mAu a nhiet dO cao cua lop ma

hop kim va crom

4.4 Anh hue ng cua ch6dO gia nhiet den call true 'Op ma, khao sat

qua hien vi dien tit quet:(SEM) va hien vi kim arcing

V Thao luan ire ker qua nghien cau dung dich, chg de) ma,

VI Xcic lap quy trinh ma izqp kim W-Co cho piston, xi lanh, kich

be phcio 122D74, co quan helm liii phcio cao xa 37, van xa lieu

6.1 Be ma

6.2 Dien cut (+)

6.3 Mdu this nghiem

6.4 Ti6n hanh ma mdu

6.5 Quy trinh ma phuc hoi, bio quan piston, xy lanh ham Eli phao

37, kich be t5, phao 122 D74, van xi lidu binh phin ang san xua't

thily tinh

6.6 Anh van xa khong ma, ma crom, ma hop kim trudc va sau

thdi gian sir dung

8-1 TOng k6t de tai

8-2 Xac nhan k6t qui this nghiem, Ling dung ldp ma hop kim

W-Co vao san xua't

4 Anh chup hinh thai ldp ma lAng hidn vi then tit' quet SEM có

do phOng dai 5000 lAn hdp kim W-Co (%W 23) 8 cac nhiet do

ram khac nhau

5 Anh chup hidn vi dien tit quilt SEM, hinh thai be' mat: Co

nguyen chat, hdp kim W-Co (%W 15%)

Vien K' Thitat Nhiiq Me;iTreering

Ma Wtrong dung dich mtdc khona th6 thtfc hien rieng re dttOc, no chi co th6 ket ttla dong thdi voi cac kim loai kliac de tao thanh hOp kim Nhieu tac gia da nghien cdu qua trinh ma dien cua W vdi kim loai nhom sat[1,7, 22]

Cac kim loai trong hop kim dttoc.sdp x6p pha trOn cac phan rieng biet hoac hon hop vo dinh hinh, hoac hinh thanh dang muoi

Nhieu tac gia da Ichang clinh hop kim W-Cola hcip kim cuing co d6 ben choeng an mon rat cao,h0p kim thu6c loai sieu ben nhiet d6 cao, ldp ma hop kim W-Co ddri thay cho kip ma crom vi no Ichgc pliuc dttdc nhfiing rihuoc diem cua ldp, ma crom nhu' kha nang phan 1)6' thap, nhieu 1-6 x6p anh huOng tdi kha nang bao ve cho'ng an mOn va tinh nang c019 thay dal khi lam viec d nhiet d6 rat cao, crac biet ma crom lam 6 nhi 7em mai truOng hai sac khoe cho ngu'di tru'c ti6p ma

Nghien aril ma hop kim theo huOng thay doi thanh phan dung dich ma them cac chat pall co, vo co lam tang tinh nang qu9 cua ldp ma hop kim, ding vdi thanh phan dung dich ma cac tac gia con chti y tdi anh hu'Ong cua ch6 d6 ma, ch6d6 xit 19 nhiet, xit 19 mAti anh huOng toi chat lttong ldp ma [1, 22, 25] Qua cac tai lieu tham khao de tai (tat ra muc tieu nhanh chong Ling dung k6t qua nghien atu vao san xuat, de tai da tien hinh khao sat so b6 mot so dung dich va ch6d0 ma phu hop, vdi dieu lcien vat Whoa chat c6 tren thi tru'disIg Viet Nam, tit do di sau vao kho sat danh gia sit phu thu6c giita thanh phan, tinh nang co 19 cua lop ma hOp kim vao thanh phan dung dich , ch6 c16, ma va ch6 d6 gia cong tru'dc va sau khi ma de, nang cao kha nang bao ve chong mOn, mat mOn, lam viec nhiet (16 cao cua cac chi ti6t dttoc ch6tao tit thep hop kim th4 Trude mat de tai thi6t lap du'oc quy trinh ma hop kim cho van nap, xa lieu cua binh phan ang ch6 tao thuy tinh long, xi lanh va pitston ham phao

37, ket qua nghien clu'oc d6 tai ma r'6ng On,„aclung cho cac chi ti6t khuon, thi6t bi chiu nhiet theo yeu cau cu the cua titng the loai De thu'c hien va hoan thanh de tai nham nghien cat' cua Vien KTND & BVMTda nhan du'oc su' gity

da qu9 bau caa, SO Khoa hoc Cong ripe thanh ph61-16 Chi Minh bang viec cap kinh phi cho de tai hoat Orig De tai nhan du'oc su' chi dan he-tssac b6 ich cua HOi clong,xet duyet 146i clang nghiem thu giai loan 1 va HOi dong nghiem thu

de tai tai nhan dude nhitng nhan xet khach quan nhu'ng he's sac khich le cua cac gido su' tien sy phan bin de de tai thu'c hien tot hon De tai con nhan

&roc su' chi dao, dOng vien gitip dd cua lanh dao va tap the can b6 CNV Vien KIND & BVMT phong DO ben vat lieu kim loai

Nhan dip k'et thilc de tai, xin thay mat nhorn can b6 nghien cau, chd nhiem

de tai xin chan thanh cam On sot gitip (la vo cung hieu qua d6

D6 tai chan thanh cam on lanh dao, can b6 cong nhan vien cac nha may, co quan dal tac nhu' ;Wang sita chGa va khi, Xi nghicp lien hiep Z751, nha may hoa chat Bien Flea D'6ng Nai da tao dieu kien cho nghien citu, ring dung

Viet: 10 Thu& Nhiet DUi & fltio Ve Trraug

Phan A: TONG QUAN

I DAC DIEM CUA M4 HOP KIM W-CO

Dd ch6 tao cac chi tilt may b'jn nhiet, an mon, mai mon a cac nu'dc cong nghi'ep tien ti6n c6 nganh luyen kim phat tridn ngudi ta thudng sit dung cac vat lieu la the') hop kim hay kV kim cao cap: Xupap xi a Ong cd d6t trong la chi tilt lam vi'ec trong cli6u kiln nang nhdt vita chiu tai trong cao, nhiet dO 650-700°C va bi an mon trong moi trudng ctia sin phgm chay, bi mai mon khi va dap, no chick ch6 tao tit hOp kim c6 cdu tit vonfram (B) 45x14B2M Cac canh tu6c bin a cac not hdi dudc lam tit thep 15xBHM4 c6 dO bi6n dang 0,1% sau 100.000 gid lam vi'ec a 540-560°C Hdp kim nimonic vdi thanh phan chu ye-u g6m: Ni, Cr, Ti, Al c6 them W, Co, Mo lam tang dO b6n nong dude dung rOng rai cid ch6 tao cac chi tilt lam vi'ec a nhiet 'TO cao trong cac dOng cd ten lira, tu6c bin khi, tau vii tru

Thep hop kim hoac hop kim c6 tinh nang co ly h6a cao gia thanh dat vi vay trong san xudt nham giim gia thanh nhung van dim bio chdt lu'Ong san pha'rn, nhiL trudng hop ngudi ta ap dung cac phdong phap fling nong hoac ma hop kim len cot thep, hoac dp dung cac cong nghe xit ly be mat nhd toi, ram, hoa, nhiet luy'en

Tren the gidi viec ke-t tua dien hoa hOp kim W-Co trong dung dich nu'dc da dudc nghien cdu dda vao (frig dung trong san xudt tit nhGng narn sau mudi cua the ky trudc do nhang clidm not bat cita ldp ma nhu' dO cuing cac, khi nang chiu mai mon, an mon, b6n trong mai tru' ng h6a chdt nhu' hop kim chda 35%

W sau khi gia nhiet dO cirng c6 thd dat tdi 1300 KG/mm2 to-c dO an ram trong H,SO4 1:1 a 20°C la 0,16 mg/cm2ngay, coban nguyen chdt la 5,3mg/cm2ngay, niken nguyen chdt la 0,59mg/cm2ngay CS nhiet dO cao 700°C W nguyen chat bi oxy hoa nhu'ng hop kim W-Co thi khong Ldp ma W-Co do c6 dac trdng iii tinh cao nen &roc sir dung dd ch6 tao tit cang cho cac thi6t bi thong tin, in an va thie-t bi din tit

Ngay nay vi'ec nghien cdu and rOng khi nang ling dung cila ldp ma hip kim W-Co van dtroc ti6p tuc then cac hudng:

- Dila them cac cdu tit kim loai, phi kim vao ldp ma dd tao thanh vat lieu dang

to hop c6 nhie'u tinh nang utu viet: tang dO deo, tang do cdng, tang khi nang chiu h6a chdt nhd clu'a Bo, TiO2, SiC vao ldp ma

- Dila cac chdt them tao phirc dd on dinh qua trinh ma hoac giim nhiet 10, tang gidi han mat dO dong nhd trong dung dich pirophotphat du'a them amonicitrat

Viers Kv Thu& Nhiet Doi & Bdo Ve Mai Tniiing

II CAC Dal Ric/NG CU THE DE AP DUNG KET QUA NGHIEN Ceti'

Nghien cdu ma hop kim W-Co nham thay cho ldp ma crom ciIng phuc h6i kha nang lam viec be mat ben trong, trong viec ch6 tao mdi cac chi ti6t nhu' xi lanh kich cang phao 130, xi lanh kich be tSt phao 122 D74, xi lanh ddi th6 CX57, xi lanh piston co quan ham lai phao cao xa 37, cac chi tieet lam viec nhiet d6 cao, ap suet ldn nhu van xa binh phan Ong sin xua-t thay tinh long , binh hdp hoi autoclave Trudc mat de tai huOng tdi hai loai dal Wong cu thd sau:

a Mg hqp kim W-Co phuc hoi kich thctoc, khd nang lam viec va the tgo mcri cdc chi tie't bi an man va mai man trong tnoi twang xelm th►,ec cao:

- Xi lanh kich be tif, xi lanh ham lui cua phao 122 D74 ; 37 Vat lieu ch6 tao la loci the') cacbon tot 50A có thanh phan % C 0,52-0,56 — Mn 0,50 — 0,80 vdi tinh nang cd ly gidi han bdri keo abk 107 N/m2 = 64 D6 dan dai tu'cing dal 5%

=17, d6 cdng bd mat sau khi toi cao tan d6 tranh bie-n clang dat tdi 59-63 HRC

- Can pitston cd quan ham lui phao 37 du'Oc ch6 tao tit thep hop kim 45X vdi thanh phdn % C: 0,42-0,50, Si: 0,37-01,38, Mn: 0,50-0,80, Cr: 0,80-1,1, Ni: 50,25 Sau khi toi cao tan dd tranh bieen dang (00 L600) tinh nang co ly: c.b(gidi han chay) 107N/m2 = 85, obk 107N/m2 = 105, 5% =9 d6 cdng b8 mat 58- 63HRC Gidi han bdri mOi ctia truc trOn trdn tang len 1,3-1,7 Lan so vd: tru'dc khi toi.Sau qua trinh sit dung bao quan cac the loci chi tier tren ddoc clu'a vao sda chda phuc hoi, Mng thdi mot s6 nha may dang nghien cdu ch6 tao chi ti6t mdi de thay th6, xong gap nhidu khd khan khi drig dung ldp ma crom vi kha nang phan b6 tha-p , ma mat trong ctia xi lanh khong dam bao chdt ldong cho thi6t bi lam viec lau dai a mai truing khi heu bidn, chu ky tra lai xu'ang 12 thang hieu qua kinh t6 va phuc vu s'in sang chitin da-u khong cao, them chi do ldp ma crom co nhi8u 15 tao nen hien tu'ong an mon clidm vao nen rat sau dan tdi viec khong the khac phuc sita chaa du'oc, anh hdang nhidu tdi chdt lu'ong trang bi cilia quan d6i va cac ldc luting vu trang

- Kich be tS, va co au ham lui cilia phao la he th6ng thily ldc sit dung diu

STEOLLM (dh xanh ngot) cd thanh phAn sau:

Vien Thud' Nhial Doi & Bdo Ve Moi TrWing

Be mat xi lanhbi an mon nhi'u nhdt là khu uric pap ranh giga khong khi, zoang cao su va dau xanh rlot thdong to nhIrng 16 sau pbu thuoc vao theh gian

va moi trtking lam viec De khdc phuc tInh tang ten de tai tien hanh nghien cdu ma hop kim W-Co phti len xi lanh thOp 50A va pitston thop 45X c6 kich thtidc 4)60, 1,600; 4)40, L600; ma phuc hot can dat 5001.1m, dO cling 900- 1000KG/mmh (Wang diking vdi lop dna crom ding), ma boo ye c6 chieu clay 15-25gm, dO cdug 900-1000KG/mm- Ichong 16 xop co kha nang phan va chong An mon tot crom, tang thOi gian chu k5, sita chga tg 12 thong len 36 thong

Anh 1 Xi lanh, piston co quan ham Anh 2 Van binh phan tin sin xudt

S6 (1): Trddc khi ma S6 (2): Sau khi ma

b Mg hipp kim W-Co tang di) an doi vdi cdc chi ti'et lam viec dadi dp hfc ldn, nhiet d() cao trong mOi trading h6a chdt

Van xi cua binh phin dng sin xudt thtly tinh long: binh co , kh6i lu'Ong 4m2, phan dng dttoc duy toP =12KG, t=200°, nguyen lieu gom NaOH = 15%, SiO2

Day lA chi tiet chiu mai mon chic% act ltic ldn nhdt là khi xi lieu vi vay no thOng du'cic the too tit thep hop kim 18X2H4BA [16] hoac 25XrM [3] co dO thAm toi cua thep vao khoara 35-60mm, co tinh cd 19 aB ?_1150MPa [16] (TB

?_1200Mpa (2) cling co the sit dung thep hop kim 12XM4) hoac hop kim, 12XM4) crom , - Niken 40XH, 45XH, 50XH co ca tinh to hop cao dun4 cue ueche

to chi tiet co thieet dien 40-50mm, do co mat cua niken trong thep nen co dO dai U nhiet dO cao, sau qua trinh tot thdm gia ding nhiet 00 cting b8 mat ldn, nhu'ng vi gia thanh cua sin,phdm daf t nen cac nha may h,da chit to 'a eking bang thep cac bon chat ldong thR5ng, co tinh thap oB P-1 380-490 Mpa

00 cdng HB< 200

Vdi vat lieu tren tuOi tho,cita van xi lieu rat thdp a-liking chi dim boo dutic

24 gi6 lam viec tuc De tai dat mac tieu tradc mast ma len phdn chop cila van xi 4)50L30 ldp hop kini.co chieu day 200 Lm, dO cdng dat &toe 900-1000 KG/mm- nham nang cao tuOt tho ctia van len 2 lan

Anh

Viet: K9 Thuds Nhiet DUi & Tido Ve Moi Tntentg

Phan B: THUG NGHIEM

I PHUING PHAP NGHIEN COI

1 ChuSri bi mdu: Mdu thep CT3, 45X thick gia tong vdi kith thu'dc 30x50x2

2 Thiet lap sd do quy trinh g6m 8 bu'dc:

Lam sach

Cd hoc

Tdy and H6a hoc

Tdy ri Hoa hoc

Xti' lyt scr b

4 Dien cu'c (+) lttdi Platin 30 x 50

5 Thi nghiem tham do d6 xdc dinh dung dich ma vdi thanh phdn kha thi

6 Nghien cdu anh tiding cila tieing a dung dich, the (10 ma, ch6d0 xis 1y nhiet tdi: hieu sat ang, thanh phAn hcfp kim ket taa, kha nang phan b6, tinh hang cci 1/ dia lOp ma nhu' (10 ctIng, d0 barn dinh, kha nang chiu nhiet, c10 ben trong axit, kiem, nirdc mu6i

- Do barn dinh gitta lop mg vg nen: chick kidm tra bang cac phuzing phdp

(phu'Ong phap nong lanh, phu'Ong phdp mai dila, phu'ong phap uon mau)

Pluong phap flung: Nung nong mau a to 250°C, gifii nhi6t dO 15 phdt, sau do lay

ra va nhung vao nadc c6 nhi6t do 15-25 'C DO b8n barn dat n6u quan sat khong tha'y hi6n tu'ong bong trOc, rOp 16p ma

Phtong phap icon mitt: U6n mat' cho (len khi gay

- Mau ding ban (Jai: 40 x 15 x 1, 2 the') 45X

- Dung cu kidm tra: et& 2 truc tron bang thep co dusting kinh 6mm, chi4u dai

Vigil RJ Thwit Nhiet Doi & Rao Ve Moi Tritinto

- Tidn hanh: Mdu kep chat gia'a hai truc dat trong ma kep eto, dung kim

va dao uo'n mau di mot goc 90° v6 mot phia va uo'n theo phia ngu'Oc 14i cho toi khi mau gay, tai ch8 gay dung dao lcidm tra do ben barn dm lop ma hOp kim voi nen thep

- Danh gia: DO barn dinh dat ndu raid quan sat khong thdy hien tdong bong troc ldp m4 (hien tu'Ong ran nat lOp mad ch8 gay khi do khong tinh ddn)

Kierm tra de) to xdp lop mg hop kim: Phu'Ong phap (rat gidy thdm

Phu'Ong phap data tren stt tu'Ong tac hoa hoc caa kim loaf nen, a day la Fe vdi chdt tha' tai nhang vi tril8 r8 caa ldp ma vOi dd thanh nhUng hOp chdt co mau

- Dung dich this: Ferixianua 10 g/l

Natriclorua 20 g/1

- Cach Chit: Thdm u'Ot gidy thdm lAng dung dich tha' va dat len be mat chi tiet sao cho giu'a be mat chi tidt va gidy khong con bot khi, vet ri in tren gidy du'di (Wig didm hoac dom Gidy thdm dutcsc nha-c khai be mat mau ra'a sach Wang nu'oc cat va say kho tren kinh sach, so diem xanh tren lcm2 dien tich gidy thdm du'Oc tinh la s6 didm 18 cila 14 m4 hop kim

Thanh phdn hvp kim, thanh phdn dung dich duOc xac clinh theo phu'Ong phap

trong lu'ong phan tich h6a hoc va tap thu nguyen tit tren thief bi Varianspeetr

AA (f.1c)

Chap kim hong, Runghen: de phan tich to chtitc t6 vi va cdu trdc hOp kim

Chugn bi mat': Mdu chup clu'Oc cat tit chi tidt ma, sao cho be mat phang caa lOp m4 vuong goc vOi mat phang caa mau soi, mau soi duvc dac trong vat lieu nhkra, mai va danh bong mau

Dd tang dO arcing phan gifia lOp m4 va nen co thd tam thqc mau soi bAng dung dich h8n he Cita axit nitric va etanol ty le: 5/95

Kha nang phan bo'clu'oc xac clinh theo phudng phap Hering Blum

- De) clanh gia kha nang ben mai mon: mau kim loci du'oc gia cong thanh tam dem tren nap col nghien bi sit va hOp kim du'oc ma len be mat mau

- 6 -

Viet: M Thu& Nhiet Doi & Thio Ve Trolinz

IL T111 NGHI$M SO BO LISA CHON DUNG DISH M4 HOP KIM

Do the phong then ctia coban va vofram cach xa nhau (-0,28v-0,58v) nen trong dung dich ddu có chit tao phirc kd ca dung dich axit Ira dung dich kidm: amonicitrat, pirophotphat, mu6i tatrat, amonihydroxit Dd giam nhiet TO ma mot s6 cong trinh nghien ctu da" data nheng thanh phAn tao phdc he mdi vao dung dich [22] nhu' 1,6 amonihecxan va 1,8 diamonioctan vdi hiong rat nhO da dat hieu qua cao

Qua tim hidu vat ttt hoa chit hien co tren thi trtrang Viet Nam va trao cloi tren mang thong tin, a tai da" chan bi cac loci dung dich sau dd khdo sat so

Viers 165 Thud: Nhiet Doi & Boo tie Mtii Trtaiwz

Dung dich cho phep mad nhiet do thdp t = 40('C giai mat TO deng rOng (0,5- 6A/dm2) nhu'ng hieu sudt clang nho 40% va thanh phdn W trong hop kim khong vu'dt qua 30%, ldp ma 201.tm bi gai nhidu

Dung dich 3: Dung dich amonicitrat

This nghiem cho thdy tit dung dich nhdn du'Oc lop ma bong min, hieu sudt clang lon, thanh phdn W trong hOp kim giai rOng phu thu'Oc vao thanh phAn dung dich va ch6 dO ma, mot y6u to rat quan trong de' de' tai lila chon la kha nang

ma day

Tit k6t qua thi nghiem tham do de' tai da lila chon dung dich amonicitrat dd nghien citu

- 8 -

Viers Ki Thuds Nhiet Dui & Ve Mo i Train

DO MA DEN THANH PHAN HOP KIM TREN SO' DUNG DICH AMONICITRAT

3.1.Anh hitang cua su thay ndng do Na2WO4 sten % W trong hop kim

Thanh phAn dung dich va che- d0 ma;

3-2 Anh frua3.ng cica mat c10 dung den thanh

Thanh phan dung dich va the dc) ma:

CoSO4.71L0

Vibe 10 Thuat Nhiet Ddi & Beio Ve Mai Trytime

phcin hop kim

Bang 3.2 Anh hu'ang cua mat (10 dung Dk den thanh phan hOp kim

Khi nCing dO dung dich va cac y6u to kladc khsong thay cldi mat do &mg catot anh lutccng thanh phan hop kim: theo chieu tang cua DK, % W tang den trang thai gars nha '<hong cloi 0 DK 3,5 vu'ot qua ,gioi han tren chat lacing be mat lop ma xau, % W trong h0p kim giam, hieu suat (long giam

Viers Kv Thruit Nhiet Ddi & Ban Ve Mói Mane

3-3 Anh ht&3ng cda nhiet c10 ma tdi trang thai be mat, to xeip va khd ncing barn dinh

Thanh phdn dung dich va che- c10 ma:

Vie,: Kit Thu& Nhiet Doi & Bno Ve Mdi Trtang

3-4 Xcic dinh khci ruing phan bo ciia dung (itch mg Op km W-Co

a Phoong phap Hering-Blum

ei day Lx, Lo khoang cach gifita anod va catod: xa, gAn (cm), k

Mg , Mx trong hiring ke't tha hOp kim: gAn, xa (g)

b Kha nang phan b6 cua dung dich ma hop kim W-Co so vdi dung dich ma crom tieu chuan

Thanh phAn dung dich va the di) ma hOp kim:

Bang 3.4 Kha nang phan b6 cita dung dich ma hOp kim W-Co so voi dung dich

ma crom tieu chuan

Nhcin xet: Kha nang phan b6 cita dung did; amonicitrat ma hop kim W-Co cao

hdn nhieu so, vdi dung dich ma crom tieu chuan vi v4y sir dung amonicitrat ma nhung chi tiet có cau hinh phtic tap hoc ma chi tiet dang 'Ong nhu' xi lanh se thu'a.n loi hcin so vdi ma crom

- 12 -

Viers Kv Thuat iVhiet Dui & Boo Ve Moi Trilling

IV KHAO SAT TINH [YANG CO Li., HOA COA LOP P44 HOP KIM W-00

Tren cci sa khao sat anh twang ctia thanh phAn dung (Lich va the dO ma den thanh pha'n hop kim, kha nano barn dinh vdi nen theRva trang thai be mat lop

ma, de tai da lila chon dung dich co thanh phan va the 60 ma sau:

Thanh pha'n dung dich va the (10 ma:

có % W ,z; 30-40 Doi vdi cac chi tiet lam viec a nhiet dO cao chin mai mon ldn, hop kim can co % W cao 50

4.1 Anh httohg caa the c1(.5 ram nhiet len de) caging caa lap mg

Khao sat anh hu'ang caa the do gia nhiet len dO cang lop ma hOp kim cho ket qua sau:

Bang 4.1.1 Anh huang cua nhiet TO ram len dO ding ldp ma hop kim W-Co (chieu day 251.tm)

TT

Nhi:et (10 ram— DO tang to vi: (Kg/mm') a: hop kim %W = 40

b: hop kim %W = 50 Killing ram Ram 200°C (2h) Ram400 °C (2h) 600°C (2h) 700°C

Welt Ki; Thrttit Nhiet Dori & Rao Ve Mai Trzaine

Bang 4.1.2 Anh hoeing caa nhiet d() ram len (10 ding to vi theo chi6u day lop

Viers M Thu& Nhiet Doti & Trohne

4.2 Ddnh gia do b'gn trong dung dich kiem, axit caa hop kim mg W-Co va kha nang bao ve cho'ng an men caa no

4.2.1 This nghirn d6 hda tan trong m6i tracing axit, ki6m, mu6i: Mdu theft

khong ri sau khi dadc ma hop kim có % W 40 du'Oc gia nhiet a 400 °C trong 2 gid, dd ngu6i va tach 1c3p ma ra kilo" nen, hOp kim clu'Oc can tru'oc khi ngam trong axit, sau thdi gian this nghi:e'm 5 ngay, hop kim du'Oc ldy ra khoi dung dich, ril'a sach, say kho va can 141 trong ladng, danh gia d6 hoa tan ctia no Tu'on.c4 tit nhu' vay doi vii lop ma Ni, Co, Cr dd danh gia c10 bdn ctia cac lop ma trong m6i trding axit, kidm, muOi

Bang 4.2.1 DO hda tan caa lop ma hop kim, kim loaf trong axit, kidm

Hop kim W-Co co 40% W trong dung dich axit HNO3, HC1 bdn hon

so vol Cr, Ni, Co, trong dung dich kim dac ming hop kim W-Co khong tan

Viers K9 Thti NIziet Dili & Biio Ve Trame

4.2.2 So sanh kha nang bao ve cho'ng an men cUa lOp ma hOp kim vOi lop ma

Crom

Phu'Ong phap phun su'cing mu6i: Mdu the') CT3 du'oc ma crom va hop kim

W-Co có cung chieu day15).1m, kha nang bao ve cila lop ma du'Oc danh gia theo tieu chugn ASTM B11: Sir dung dung dich 5% NaC1 d 35°C pH = 3 (clidu chinh

pH bang axit acetic) thdi gian phun 72 gid — Thie't bi to su'Ong mu6i SSC 1000 Bang 4.2.2.1 So sanh kha nang bao ve cho'ng an men ctia lop ma hOp kim

voci lOp ma Crom tieu chugn bang phu'Ong phap phun stidng mu&

Nhi -Ot dO ram °C Sy' thay cai trgng lactng va trgng thdi be mat mein sau thik nghi"On

Khong ram Trong lu'on2 khong thay cl6i — lop ma bong sang

200°C Trong lu'Ong khong thay d6i — lop ma bong sang

400°C Trong lu'ong khong thay d6i — lOp ma bong sang

600°C Trong lu'ong khong thay d6i

Crom Trong hiOng tang 0, 2 mg/dm2 — lop ma co nhieu vet ri

- Phtrong phap do phan trong dung dich NaCI 3%, sir dung may do tong tra

do theo che'd(5 Potentiostate nhd Autolab PB Stale 30

- Ke't qua do dac du'oc the hien tren bang

Bang 4.9.2.7 Danh gia kha nang bao ve cho-ng an mOn Wang phtkrng phap phan cue

Nkin xet:

Lop ma hOp kim co kha nang bao ve ch6ng an mOn tot hon nhieu so voi lop

ma crom co cung chieu day 151.tm

- 16 -

Thuat iVhiet Dtii & Btio Ve Mei TritOliz

Kha ruing bao ve cheing an mem caa lop me) hop kim W-Co % W 40 cloi vdi thep cac bon trong thiu thuy 11,tc STEOL-M (ciciu xanh ngot)

DAu thuy ltic STEOL-M clu'Oc dung trong he th6ng thuy laic cua vu khi b6 binh he 1 nhu' kich be tSt co ciu ham lui cac loci phao co thanh phdn sau:

- Chidu day lop ma 151.tm

- Ngam 2/3 mau chim trong dau

- Thai gian ngam 15 thang

- Binh thily tinh ngam clu'Oc Tat trong tti citing cac h6a chit bay hdi nhd HCI, HNO3

Bang 4.2.3 Kha nang bao ve ch6ng an man trong cidu STEOL-M a m6i tru'ang xam thkic manh

Thbi gian

ngam man

(timing)

3 Khong xudt hien vet ri, mau xam Mau sang trdng co vet ri xuatt hien

5 Khong xudt hien vet ri, mau xam du Nhieu vett ri

6 Khong xudt hien vet ri, mau xam du Ri rat nhi6u

7 Khong xudt hien vet ri, mau xam deu Ri rat nhieu

8 Khong xudt hien vet ri, mau xam deu Ri tit nhi8u

9 Khong xuatt hien vet ri, mau xam au Ri rat nhieu

15 Khong xuatt hien vet ri, mau xam au Ri rat nhieu

Nhiin xet:

Ke't qua cho thiy vsoi lop ma co ding chidu day 151Arn kha nang b4o ve chong an man trong dau STEOL-M caa lop ma hop kim % W 38 — 40 tot hOn rat nhieu so vdi lop ma crom khi dat d moi tru'ang co tac nhan an man manh

Vida ICY ThuOt Nhift Doi & Boo 11 MOi Trilling

Anh 3 This nghidm khd nang bdo vd ch6ng an mon ciia Op ma hop kim W-Co

- Phun strong mu6i: (Mau 1: ma Crom; Mau 2&3: ma hop kim W-Co, (40%W)

- Phan ckic anod : (Mau 4: ma crom; Mau 5& 6: ma hOp kim W-Co)

Anh 4 Thu' nghidm ngam mdu ma hop kim va Crom trong dau CTEOL-M 9 thang M7du ma hop kim W-Co(1) Mau ma crom (2) Chidu day lOp ma: 15pm

- 18 -

yip K Tliudt Nhie1 Doi & Bdo Ve Mai Trilling

4.3 Thy' nghiem khd ?Ong bdo ve caa lop ma kip kim va crom nhiet 610 cao: liau the!, duvc mg 1/3 dien tick be *it, dwic nung trong It nung c6 he dau chlnh nhiet, thai gian nung 5 sau de nguOi trong lb

Tilt& khi nung

Sau khi nung

900°C 1100 1150 -1200 PhAn ma bi tham mail

PhAn khong ma hoc ldp 941 930

Bi oxy hda mau sam

1200°C 1100 1150 - 1200 Toan b() bd mat bi oxy

Ma mau dm 941 773 B oxy hda mail sam i

Nhan zet:

- d nhit do cao ldp ma W-Co bi oxy hba be mat lOp mong, 00 cling it thay

- LOp ma crom bi oxy hba lop mang, song c10 cdng be mat giam nhi6u

- Phdn kim loci khong &foe ma bi oxy hoa hoc 14

Anh 5 This ngh*n nung mdum4 hop kim trong 5 gid

1 400°C

2 900°C

3 1200°C

Vie?! KP Thu& Nhiet Ddi & Rho Ve ,V1iii Trilling

4.4 Khd nang bdo ve cho'ng mai man clia hop kim W-Co so vdi lop mg Crom

Dd khao sat kha nang bao ve ch6ng mai mon caa ldp ma W-Co so vdi ldp ma crom, (16 tai da ma hOp kim va crom len tam 45X, (I) = 30mm, chidu day lop

ma 200p.m, mau ma du'cic Binh chat tren nap cila c6i nghien bi sit V=200m1, trong lOng c6i trOn 100g cat yang, 20 vien sir (1)8, c6i &roc clat vao may quay ngang vdi t6c do 150vOng/phtit, c10 mai mOn clack tinh theo cong thac sau:

m —m,

171

day: - m i : la trong lucing mdu trifdc khi nghie'n

- m2 : trong lacing rnau sau khi nghidn

- t : thdi gian nghi'dn (gid)

Ke-t qua dacic thd hien nhu' sau:

Bang 4.4 Khdo sat kha nang bao ve ch6ng mai mon clia hop kim W-Co so vdi lop ma Crom tieu chudn

TT gia nhiet

2 gib'

Lop ma ho kim 50 : 50 Lop ma crom

DO cii ng(KG/mm2 ) dm (g/gib) DOcang(KG/mm2 ) dm (g/gib)

t

-20-

Viers Thu& Nhiet Doi & Biio Ire Trztitne

Khdo sat, phon tich cdu trac lop mg hop kim qua soi chup kim twang, hien vi (lien tet quet (SEM)

K6t qua chup kim =rig có do phong dai 1000 ldn: Lop ma hdp kim W-Co (50:50) tren nen the') 45

Anh 6 Trudc gia nhiet (a), sau gia nhiet a 200°C trong 2 gib (b), sau gia nhiet

400°C (c), sau gia nhiet d 600°C trong 2 gib (d)

N/ian xet:

Nhiet do ram > 200°C xudt hien khu6ch tan giQ'a Idp ma va nen lam cho ldp

Vin icy Thuat Nhif1 Dei & Bdo Ve Mei Trilling

Anh chup hidn vi din tiY quet (SEM)

Anh 7 Chu') SEM: Hop kim W-Co (40:60) trikic gia nhiOt (a), sau gia nhiOt (b)

400°C trong 2 gid

Nh2n xet:

Tnfdc gia nhiOt cau truc tinh thd dang hat ton có kich thu'dc 200-500mm

Sau gia nhiOt kich thUOc hat 100 mm, vi vay ldp ma min,cdng hon

-22-

Viet, Kv Thtuit Nhiet Beti & Biio Ve Al& Trtfilite

Ron ghen: Mdu hdp kim W-Co (50:50)

A -,ly Leh .o-rar-2025 14 45

Trddc khi gia nhiet keet tinh chda on dinh

Sau khi gianhiet tren gian d6 xua't hien 3 vach nhieu x4 ro rang, a gia tri

d(A) rat gan vdi gia tri cua pha W, co the da xua't hien clang ket tinh Co3W

[22]

Gian (16 pha cho tha'y ke't tux dien hod h'Op kin W-Co thu(ic dang vo dinh

hinh

Viet: Ky Thutit Nhiet Doi & Bao Ve moi Traute

NANG CC LY HOA LOT MA HO KIM W-Co

Tit ket qua thi nghiem tham do de tai da ltta chon dung dich amonicitrat dd khao sat thanh phan dung dich , the dO ma nhhm tim ra cac thong s6 t6i au

- Anh httong cua n'dng do [Na2WO4J trong dung dich din % W trong hop kim

khi n(ing de? [CoSO4] va [(NH4)3C6H507] c6 dinh d 45±2 va 80±2(g/1), Dic-2A/dm2 dtrOc the hien ct (bang 3-1, hinh 1) cho thdy ham 'Yong W trong hop kim tang khi tieing dO mu6i vonfram trong dung dich tang va dat clic dai khi [Na2W04 21-120] z:70g/1, Cf khoang tit 58 — 70g/I cho lop ma bong sang nha'n, tiep tkic tang n6ng dO muol, %W trong hdp kim giam, chdt luring kip ma giam,

bi gai

Ket qua khao sat cdu trac lop ma tren hidn vi dien tit quet lop Zabdel Hamid [22] da chting minh cau trot tinh the caa coban sach la dang vien tren, kith thadc hat 1 - 2p.m, khi co mat caa W cdu trot tinh han, hdp kim %W = 15 ldp

ma có dac trong dang scri vdi kith thu'dc hat 300-400nm (Anh 6) ldp ma hOp kim min hon dO c(tng cao hdn so vdi ldp ma Coban

- Anh hdOng ctia mit do clang len %W trong hop kim: (Bang 3-2, hinh 2), khi

c6 dinh n6ng do t6i u'u caa mu6i coban, mu6i vonfram, amonicitrat, nhiet (10

ma, khi thay d6i mat 'TO &mg tit 0,5 — 4,0A/dm2 cho ke't qua sau: m'a't do: tang

%W trong hop kim tang den clic dai (52 — 54%) 3,0 — 3,5A/dm'- sau do giam, ang thdi vdi viec giam %W chdt luring ldp ma va hieu sat clang ding giam theo, co the giai thich do hydro phong dien manh liet Ct mat c10 clang cao lam giam hieu ti'ng tiep xLic cila ion W den be mat catod ang theci tao nhi8u gai tren ke't taa

- Anh hudng ctia nhiet do cten chat luring lOp mg (Bang 3-3)

Voi chi6u tang caa nhiet 00 ma tit' 50 — 90°C lop ma tra nen trhng sang bOng khoang 70 — 80°C, thdp hdn khoang nhiet dO tren lop ma khong sang bong, cao hdn 80°C ria mep bi gai.Theo quan diem ctia Z.Hamid [25] sti tang nhiet do

lam cho qua trinh dich chuydn ion W den sat be mat catod d8 clang hdn, %W trong hdp kim tang lop ma có cdu trtic tinh hdn , b8 mat nha'n bong sang hdn, vu'cit qua gidi han nhiet dO t6i ttu - Chdt luring Idp ma giam do hien tu'ong hydro pilot-1g dien nhi8u lam cho dung dich sat catod bi kim hoa dan tdi hien tu'ong gai ria mei) vat ma

Viers KI7 Thuiit NM& Doi & Bdo Vg Mei Trilling

Kdt qui thi nghiem cho thiy: Vdi ldp ma hOp kim 15p.m, tidn hanh ma 8

bd co thanh phdn dung dich va che (10 sau: 65g/1 Na,W04.2H2O, 45g/1 CoSO4.7H,0, 85 g/1 (NH4)3C6H507, DK = 2A/dm2, t =70 — 80°C se cho ldp ma hop kim c6 %W 38 — 42, chit lu'ong ldp ma tu'ong cl6i On dinh khi ma day > 15pm

- Hieu cing caa gia nhiet din lop mg hqp kim W-Co

Hinh thai cua ldp ma hOp kim trticsc va sau gia nhiet duOc nghien cdu Wang viec chup hidn vi dien ti? quet SEM, vdi hcfp kim co % W 40 (Anh 7) Cali trac truoc khi gia nhiet hat nhO co kich thudc khoing 200 — 500nm, sau khi gia nhiet cau trilc tra nen chat che, du'Oc nen gon, hat co kich tint& 100nm, hinh anh (PL4) chup SEM do Z.Hamid nhan clu'Oc khi khao sat hqp kim 23 %W cho keft qui ro net Theo quan didm ctia Refs [22] 8 nhiet do gia nhiet 400°C ldp

ma tao pha cdng Co3W (Anh 8) va theo quan didm cia N-P Phedochep [1] nhiet (10 ram 600°C cac bon trong kim loci nen the') khudch tan len be mat tao vdi W d lop ma thanh cac bit lam cho (10 cling ldp ma tang len

Anh Wang cua che (10 gia nhiet din c10 cCtng cia ldp ma hOp kim duet the hien tren (bang 4.1, hinh 3) DO ding cia ldp ma chu'a gia nhiet dat 650KG/mm2, khi gia nhiet 8 200°C (10 ding clat 700KG/mm2, gia nhiet Cf 400°C , 600°C trong thdi gian 2h TO ding ldp ma dal 900 — 1000 va 1100 —1200KG/mm2 HInh chup kim tu'Ong [Anh 6, a,b,c,d] vdi dO phong dai 1000 lan cho thiy ci nhiet do 400, 600°C co hien tu'ong khudch tan gia nen vdi ldp ma tao nen (10 gin barn chic va CAI trite lop ma có stf thay doi flint phAn tren da trinh bay

- Gia nhiet anh &tang tai kha nang bao ve thong mai mon

DO ding ldp hcrp kim tang khi gia nhiet cling lam tang kha nang bio ve ch6ng mai mon cia no (bang 4-4), khi cling chd (10 ram nhiet (thdi gian, nhiet (10 ) do ding t6 vi giam theo chieu day ldp ma (bang 4.1.2), clol vdi lop ma day

100 im dO cling chu ydu phu thuOc vao thanh phin hop kim, nhiet TO ram > 400°C it anh twang tdi dO tang lop ma

- So sdnh khii ming bao ve thong an mon, mai mon, chiu nhiet giaa lap mg

hqp kim voi lop ma crom

Do khi nang phan b6 cila dung dich ma hOp kim so vdi vdi dung dich ma crom tieu chua'n cho kdt qua: kha nang phan b6 dm dung dich ma hop kim la +30%, kha nang phan b6 cua dung dich ma crom la —23% ninr vay ma hOp kim cho nhang chi tidt co cau hinh-phdc tap thuan loi horn so vdi ma crom, (Bing 3- 4)

Keft qui thir nghiem an mon trong to strong mu6i theo tieu chugn

Viet: by Thu& Nhiet Doi & Bao Ve Moi Trzaing

bang 4.2.2.2, anh 3) cho thay ding chiu day lop ma kha nang bao v6 ch6ng an man ctia lOp ma hdp kim da du'Oc gia nhi6t a 400 — 600°C tot hdn nhi6u so vdi lop ma crom drng, this nghi6rn phun su'dng mu6i dung dich NaCI 5% trong 72 gib, lop ma hop kim thd hi6n kha nang bao ve tot hdn so vdi lop ma crom ding chiu day 15pm

Thir nghi6m kha nang bao ve ch6ng an mon cua lOp ma hdp kim so vdi lop

ma crom, sau 15 thang ngam mau trong dau CTEOL-M binh thit nghi6m du'oc dat trong moi trtiong xam thtic cao cho day tren mau ma crom xua-t hi6n vet ri tit thang thd 3 nha-t IA ndi ti6p giap khong khi vdi clau (Bang 4.2.3, anh 4), vet ri ngay cang nhi6u, theo thdi gian all/ nghi6m d mat' ma hdp kim b6 mat lop ma có chuy6n mau toi hdn song khong có vet ri cho den thang this 15 K6t qua pha hop vdi xac nhan dia Z751 tren nhang mau the') hop kim dd ch6 tao kich be tS, co quan ham lui cac loci phdob0 binh (Xac nhan ke-t qua nghien cdu 1,2)

DI 1dt qua this nghi6m nung mau mad 900 — 1200°C trong 5 gid va cid nguOi tit nhien trong to (Bang 4-3) cho day dO cilng lOp ma hdp kim it bie-ri lop ma bi den be i ldp oxy hoa rat mong, khong anh hding nhi6u toi kha nang bao ve ch6ng mai mon, cling chiu day ,•;-, 20pm nhttrig vdi nhi6t d() nung cao do cang cua lOp ma crom giam ang thdi giam kha nang bao ve ch6ng mai caa no (Bang 4-4)

Ke't

1- Lop ma hdp kim vOi%Wc-- 40 co kha nang bao ve ch6ng an mon rat tot cho cac chi ti6t du'oc ch6 tao bang thep cac bon hay thep hdp kim tha-p trong moi traing xam thqc cao nhu' dung dich axit, Ici6m, mu6i NaCI va trong clau thily hic xanh ngot

Ke-t qua thi nghi6rn cho thdy kha nang phan b6 cila dung dich ma hop kim

W-Co, kha nang bao v6 ch6ng an mon cila lop ma hop kim so vdi lop ma crom tieu chan co ding chi6u day d6u thd hi6n titth u'u vi6t hdn, chiu day lcIp ma hOp kim 15 p.m a khong con to x6p

2- D6 tang cu'dng 'chi nang chiu nhi6t cho cac chi ti6t doi hoi lam vi6c lau dai nhi6t c10 cao can lila chon dung dich va ch6 di) ma dd nhan hop kim vdi

%WP '50 ke-t qua thfrighi6m cho thay sau khi nung 900-1200°C dO arng cua ldp

ma hop kim it thay d6i clan toi kha nang chiu mai mon tot hdn so vdi 14 ma crom c6 do cling bi giam vdi ding nhi6t do nung

-26-

Viet, Ky That Nhiet Ddf & Bao V4 Mai Tr: ding

3- Dung dich, the dO ma hOp kim bao ye va phuc h6i kich thu'dc cac chi tit the tao tit the') cacbon 50A, the') hop kim 45X

Thanh phan dung dich va che- c10 ma:

Hop kim nh4n du'oc có %W z40 ± 2

4- 14c chon dung dich, the dO ma hop kim de bao ye va phuc he3i cac chi tier lam viec a nhiet dO cao

Thanh phan dung dich ma va chel d0 ma:

Vien M Thuat Nhiet Ddi & Rao Ve :115i Trttiniz

vl XAC LAP QUY MINH MA HOP KIM W-CO CHO PISTON, XI LANH KICH BE TI' PHAO 122 D74, QUAN HAM Lill PHAO CAO LA 37, VAN

XA LIEU CUA BliVH PHAN ONG SAN XUAT THUY TINH LONG

6.1 Be mg: bd nhu'a hinh tru (I) 200, h 800 du'dc dat trong he th6ng on dinh nhiet

6.2 Dien cc:a (+)

Dien cktc (+) chuan bi tit day toc bong dien, trong cong nghe chd tao day toc vonfram ngu'di to da them Th02 (0,75-2%) vi vay can lam sach day toc tradc khi sit dung Th02 tan rat tot trong axit HCl loang [28] vi vay tru'dc khi gia cong dien cu'c can ngam day toe trong dung dich axit HCl (1:1) 12 gid, sau khi rita sach Wang nu'oc may, trang nu'dc cat 1 ldn, Vic say Icho

Chuan bi 6ng nhu'a (1)14 du'dc khoan to(I) 4 tren be mat

0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0

0 00 00000 00 000

- Du'a day toc W vao long 6ng nhu'a, (Ida tit tit tang lu'Ong nho va nen chat

- Can 6ng nhkra tru'dc va sau dd bidt lu'ong W du'dc nen ben trong

- Kidm tra do d'an tang didm 176 tren 6ng nhiia tru'dc khi boc vai du de chAn

ban cho dung dich trong qua trinh ma

6.3 Mdu thCr nghiem

M'Au this ngh*n la ton day 0.5 du'dc gia cong theo kich thiidc caa xi lanh cl) 60 L600, sau khi sach, mat ngoai du'dc cach ly dung dich bang keo, dien arc (+) vonfram du'dc du'a vao long cua mau, c6 dinh dd khoing cach to (+) tdi be mat trong ciia mdu la deu nhau, gia cong Ong suc khi vita khit vcfi phia long caa 6ng

6.4 Tidn hanh ma mAu

Thanh phdn dung dich va chd (10 ma:

Vie,: Ky Thutit Nhiet Dui & Bdo Ve AI& Trattiz

Bang 6 Anh htiOng caa to-c dO suc khi den do c16'ng ddu ctia lisp ma hop kim

10 140 120 150 135 130 140 136 135 138 Be mat nhieu soc

Be' mat nhie*u soc

20 270 230 290 275 250 280 265 260 265

Nhcirz xet:

Khi cdc yeu to khac nhu' thanh phan dung dich, che'd0 ma khong ddi to.c do suc khi da anh hu'ang toi d(5 d'Ong ddu cda chidu day Idp ma, trong clidu kien cu thd nen chon t6c do suc khi la 1,0 lit/phdt.lit, vu'ot qud to-c do tren bd mat lop ma se xudt hien v6 soc sau tao nen 136i du ing thodt khi

6.5 Quy trinh ma phuc hoi, bao quan piston, xi lanh ham lui phdo 37, Icich be

tS, phdo 122 D74, van xa binh phan i?ng san xudt thily tinh lOng

Quy trinh Om 8 bu'dc

But& 1 Sau khi da so 130 lam sach dAu and bang xang hoac dung moi haa co, can gia ding co kill (mai bao ) dd loci b6 khuydt tat va tao d(') d'Ong ddu tren

bd mat chi ti6t

Bu'oc 2 Tgy and boa hoc va dien hoa trong dung dich kidm, la bu'dc can thidt chung cho cong nghe ma

Viet, Ki; Thu& Nhiet Doi & Btio Ves Mai Train

Bu'dc 3+4 fay ri trong dung dich h6n hOp HC1 + H2SO4, sau CS)/ ri n6u ma theo ch6 d6 phuc h6i phai xam thiic trong dung dich H2SO4 70% theo phu'ong phap gia cong du'ong cu'c, am clic la chi, mat d6 dung anod 20-40A/dm2 Be mat nhan du'oc sau gia ding la mau tr.ang srfa, ang au th6i gian xam thu'c 2 phtit

Back 5 Ma ldp trung gian trong dung dich c6 thanh pha'n va ch6d6 ma sau:

Thanh phan dung dich va ch6 d6 ma:

T6c dO suc khi V = 1,0 ± 0,111t/plult.lit

Lop ma lot hop kim trung gian Co-Ni barn rat chAc tren nen va c6 dO cuing cao [4] ang thai no lam tang dO On barn cila hop kim W-Co len nen thep cac bon, thep hop kim (45, 45X, 50A) la nhang loci the') dung de gia cong chi ti6t xi lanh, pisiton ham lui, kich be tS, cua phao

- 30 -

Via 1(9 Thant Nhiet &m & Bao Trtaine

BtOc 6 Ma hop kim W-Co

a Lap rap chi tie-t vao bd ma clu'Oc thd hien tren hinh

Be ma chtla dung dich

1 Ngu6n c6 he di:6u chinh

2 Dien cite W (+)

3 Xi lanh can m4 trong

4 De- da xi lanh bang nhu'a

5 Bdm thdi khi có van kh6ng chd t6c TO

b Ma du'oc tidn hanh trong dung dich (6-4)

c T6c d() suc khi 1,0 ± 0,11it/phdt.lit

d Tinh toan:B6 sung thanh phan mu6i trong dung dich

Thufit Nhiet DOI & Bao Ve Moi Trance

- Di6n W tan nen qua trinh ma can b6 xung thanh phan mu6i coban, vi6c b6 xung clirdc thqc hien qua k6t qua phan tich dung dich, song cling có the thirc hi6n theo tinh toan thu'c nghi6m: dhOp kim = (W:Co 40:60) = 11, 34g/cm3

Diking liking di6n hoa cua hdp kim = 0, 963g/A.gid

DO day trung binh cua ldp ma trong mot gid [5]

8 Dk ri.a.t 2,75.0,963 _ 13,Linzi gi

y 11,34.1000

8 day: - Dk 11-14t cid clang catod (A/dm2)

- q hi6u swat &mg (%)

- a throng luring din hoa hop kim (g/A.gi)

- t thdi gian (gin)

- 1 chi6u dai xi lanh

- S b6 mat trong caa xi lanh 2rER x 1 11,3dm2

- Lu'dng k6t taa hop kim trong 1 gid = S x 8 ::=1 1,47cm3 = 16,7 gam Suy ra lu'ong co ban k6t tua trong 1 gid (60%) = 10 gam

- Sau m6i gid din phan can b6 xung 47,7 gam mu6i CoSO4.7H20 da du'Oc chugn bi thanh dung dich dun ming 80°C, vi6c b6 xung lam cho n6ng dd [CoSO4.7H20]:=;45±2 g/1

Bitoc 7 Gia nhi'et

- Sau khi k6t thac qua trinh ma, chi ti6t du'oc ra'a sach bang nu'oc may, ngam trong nu'dc nong, gia nhi6t d 400°C trong 2-4 gid

Btak 8 Bao quan ski dung

-1)6i voi xi lanh, piston ma theo ch6 dd bao v6 ch6ng an mon va tang dd cdrig b6 mat — chi6u day lop ma 25p.m, sau khi gia nhi6t chi can danh bong be mat

va ra lai phgn gd mep loaf bo phan du' n6u có, sau do lap rap va son phu phia ngoai vó

- D6i vii chi ti6t ma theo ch6 dd phuc hoi kich thu'dc lam vi6c, chi6u day lisp

ma ion 200-500 p.m, sau khi gia nhi6t can ti6n hanh gia cong cd khi , nhu' mai chinh xac, sau do mdi duoc phep lap rap sit clung

Tom tat ke't qua mg tren piston, xi lanh co- cdu ham lai, kich be ty cua phdo

+ Chi6u day hai ldp hop kim Co-Ni, Co-W : 0-500p.m

+ Dd barn dinh giga Op ma va nen rat tot qua thtl nghi6m

+ Dd ding 136 mat sau gia nhi6t dat 900 -1000 KG/mm2 (XN 1,2)

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