Phan Quang The va cs Tap chi KHOA HOC & CONG NGHE 78(02): 3 - 7
ANH HirOfNG CUA THONG SO QUA TRINH T 6 I D O ClTNG TE VI CUA LOfP MA COMPOSITE
, , , Phan Quang Thi*, Nguyen flang Binh, TrSn Minh Diic, Ly Viet Anh Trudng Dgi hgc Ky thuat Cong nghiep - DH Thai Nguyen TOM TAT
Mot trong nhirng bien phap dk tang kha nang chdng mon ciia lop ma composite tren nen Ni la thay d6i thong s6 qua trinh dl tang do cung tk vi ciia lop ma. Ket qua nghien ciiu ma composite AI2O3 va Ti02 tren nen Ni chi ra rSng do ciing tk vi cua lop ma composite phu thuoc dang ke vao toe do khuay, mat do dong dien va nhiet do cua dung djch dien phan. Thay doi cac thong so nay trong -•' qua trinh ma c6 the tao dugc lop ma composite co do ciing te vi gap hon 2 lan so vol lop do cung
te vi ciia lap ma Ni thong thuong.
:;;: Tu- khoa: Mg composite; NI-AI2O3; Thdng sd mg composite; Van tdc khudy; Do cimg te vl MO DAU
Ma composite nham tao ra lop ma tren nen kim loai, hop kim, chat deo. Lop ma composite tren nen Ni co ca tinh dac biet nham tang kha nang lam viec ciia cbi tiet may trong dieu kien mon va an mon. Nguyen ly va CO che ma composite dugc neu ro trong cac tai lieu tham khao [1]. Cac thong so qua trinh ma composite nhu mat do dong dien, che dp xung, toe do khuay, nhiet do dung djch dien phan, do pH co anh huong true tiep den cau triic va co tinh ciia lop ma composite [2].
Mat do dong dien dugc xac dinh theo cong thu-csau:CE= 100.WA.,/WTheo
- CE la mat do dong dien
- WACI la khoi lugng thuc ciia lop ma
- Wiheo la khoi luong ma ly tuong tinh theo djnh luat Faraday
Mat do dong dien co the la mot thong so dugc khao sat rong nhk. Mat do dong dien co anh huong rk it hoac gan nhu khong co anh huang den s6 cac hat bam vao lop ma. E)6i voi be Ni-Ti02 a toe do khuSy cao thi diem cue dai ciia thanh phSn cac hat bam vao lop ma se dich chuyen v^ phia mat do dong dien cao. Tuong tu vai he Cr-AhO., thi khi mat do cac hat trung tinh trong be ma tang len thi mot dilm cue tieu dugc tao nen ve phia mat do dong dien thap [2].
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Ngoai viec van chuyen cac hat, viec khuay cung CO tac dung giiJ cac hat lo' liing va on dinh su la lung ciia cac hat nay. Ca viec khuay dung dich dien phan va tron hat ciing voi dung dich dien phan deu co tac dung lam tan cac cue do cac hat trung tinh von lai. De tao nen su dong deu cho lop ma, dung djch huyen phu cSn chiia nhQng hat inin phan tan [3,4].
Anh huong ciia nhiet do duong nhu khac nhau doi voi cac he ma composite. Voi he Ni- AI2O3, anh huong cua nhiet do toi phan tram cac hat tham gia vao lop ma la khong dang ke. Tuy nhien, thanh phan graphite trong lop ma Cr tang len cung nhiet do toi 50°C. Trong khi do Cr- AbOj tbi ngugc lai hoan toan nghTa la cac hat ciing tham gia vao lop ma giam khi tang nhiet do tai 50°C. Trong ca hai truang hgp tac dung cua nhiet do khi tang tren 50°C co the bo qua. Doi vai he Ni-V205 thanh phan hat ciing tham gia vao lop ma la lon nhat a 50°C. Phan tram khoi lugng cac bat cung tham gia vao lop ma Cu giam lien tuc khi tang nhiet do [3,5].
Anh huong cua toe do khuay, mat do dong dien, nhiet dp ma den dp ciing te vi cua lop ma composite AbO^ va Ti02 tren nen Ni trong dieu kien phong thi nghiem tai truang Dai hgc Ky thuat Cong nghiep dugc trinh bay duai day.
THi NGHIEM Thiet bj thi nghiem
Thiet bj ma composite tren nen Ni do nhom nghien ciiu tu thiet ke va che tao bao gom be chiia dung dich dien phan dung tich 60 lit, he 3
Phan Quang The vd cs Tap chi KHOA HOC & CONG NGHE 78(02): 3-7 thdng gia nhiet tu dgng dong ngat dien co the
nang va on djnh nhiet dp ciia dung dich toi 80°C, he thong dieu khien tu dong cung cap dong mpt chieu xung hoac lien tuc cho be ma, he thong khuay ca hpc co the dieu chinh vo cap toe do khuay tu 10 v/p den 350 v/p.
Hoa chat
Cac hoa chat su- dung cho qua trinh ma composite Ni liet ke trong bang 1.
Sodium dodecyl sulfate dugc sii' dung la chat phu gia de tang hoat tinh be mat cua cac hat trung tinh. Hat trung tinh sir dung trong thi nghiem la AI2O3 vai co hat < 1 pm, TiOa voi co- hat < 300 nm va co chung ham lupng la 50g/l.
Che do va qua trinh chuan bj
Qua trinh ma dugc thuc hien voi dp pH ciia dung djch trong khoang tir 4 + 4,5 (do pH dugc dieu chinh bang each cho them NH3 hoac axit HCl loang); tan so xung sii dung trong thi nghiem la 200 Hz; ty le xung thuan/
nghich la 80%.
a. Che do mg Ni-Al203
- Thay d6i tdc do khuay tu- 140 v/p den 312 v/p Nhiet dp ma 40°C, mat do dong dien 5A/ dm".
- Thay doi mat dp dong dien: 3A/dm , 5A/dm^ 7A/dm^
Nhiet dp ma 40°C, t6c dp khuay 210 v/p.
- Thay doi nhiet do ma: 35°C, 40°C, 45°C, 50°C Mat dp dong dien 5A/dm^, toe dp khuay 210 v/p.
b. Chd do mg Ni-Ti02
- Thay doi toe dp khuay tu 140 v/p den 245 v/p Nhiet dp ma 40°C, mat dp dong dien 5A/ dm'.
- Thay doi mat dp dong dien: 3A/dm^, 5A/dm^ 7A/dm-
Nhiet dp ma 40°C, t6c dp khuay 210 v/p.
- Thay d6i nhiet dp ma: 35°C, 40°C, 45°C Toe dp khuSy 210 v/p, mat dp dong dien 5A/dm^
Truoc khi ma dung djch huyen phu dugc khuay bSng may khuay sieu am SW3H ciia Thuy sy trong 30 phiit, sau do khuay ca hoc trong be ma trong 6 gia.
M I U ma composite la thep 09CrSi, toi dat do Cling HRC = 58-60, dang hinh tru kich thuoc d = 26 mm, h = 10 mm dugc danh bong, sau do lam sach, riia trong be hon hgp axit loang d nhiet do moi truong truac khi ma. Trong qua trinh ma, dung djch huyen phu dugc khu§y CO hgc voi toe do neu tren trong thdi gian 1,5 gid. Sau khi ma, mau dugc rua trong nude chay, sau do dugc rua sieu am trong nude cat khoang 10 phiit.
KET QUA THI NGHIEM
Chieu day lap ma tren chi tiet do tren kinh hien vi quang hgc dat dugc tii- 50pm -^ 70 pm.
Mau dugc mai tren giay nhap cd 800, 1000, 1200 sau do danh bdng tren may danh bdng kim loai hpc cua Dai Loan bang bdt kim cuo-ng 1 pm sau dd tam thuc trong dung djch Nital 2% trong thdi gian 1 phiit. Dp ciing te vi ciia lap ma dugc do tren may do do cung te vi Future fm 700e ciia Nhat, tai trgng 10 gram cho ket qua tren bang 2, 3, 4.
a. Lap mg composite Ni-A^Os Bang 1. Cac boa chat sir dung cho qua trinh ma composite Al203-Ni va Tib2-Ni Hoa chat
Ham lugng
NiS04.6H,0 (g/1)
300
NiCU.eHjO (g/1)
50
H3BO3 (g/1)
40
Sodium dodecyl sulfate (g/1)
0,1
Bang 2. Do cung tl vi cua lop ma Ni-Al203, khi thay doi toe do khuay til' 140 v/p den 312 v/p, nhiet do ma 40°C, mat do dong dien 5A/dml . ,;:..';,
Lan do 1 2 3 Trung binh
Ni 154 184 170 170
Ni-ALO, 140 v/p
225 230 200 218
Ni-Al203 175 v/p
280 260 290 273
Ni-Al203 210 v/p
280 270 270 273
Ni-Al203 245 v/p
300 300 310 303
Ni-AlzOj 278 v/p
300 250 220 256
Ni-ALO, 312 v/p
200 210 310 240
Phan Quang Thi va cs Tap chi KHOA HOC & GONG NGHE 78(02):
Bang 3. Do cirng te vi cua lop ma Ni-AbOs, khi thay doi mat do dong dien: 3 A/dm", 5A/dm-, 7A/dm"
nhiet do ma 40°C, toe do khuay 210 v/p.
Lan do 1 2 3 Trung binh
Bang 4. D o
Lan do 1 2 3 Trung binh
Ni 154 184 170 170 Cling te vi cua
Ni 154 114 170 170
lop
N 3
i-ALO, A/dm-
250 210 160 206 maNi-Al203, khi i dong dien 5A/dm^,
Ni-ALO;
35°C 300 160 160 206
Ni-ALOj 5A/dm-
280 270 270 273
thay d6i nhiet do m a 35°C, 40°C, , toe do khuay
Ni-ALOs 40°C
280 270 270 273
210 v/p.
Ni-ALOj 45°C
420 380 350 383
Ni-AbO, 7A'dm-
170 200 200 190 45°C, 50°C, mat do
Ni-ALOj 50°C
290 300 280 290 Bang 5. Do cung te vi ciia lop ma composite Ni-Ti02 khi thay d6i toe do khuly tu 140 v/p din 245 v/p,
nhiet do ma 40°C, mat do dong dien 5 A/ dm".
Lan do 1 2 3 Trung binh
Ni 154 184 170 170
Ni-TiOj 140 v/p 240 235 222 232
Ni-TiOj 175 v/p
250 230 250 243
Ni-Ti02 210 v/p
225 240 230 230
Ni-Ti02 245 v/p
160 213 200 191 Bang 6. Do ciing te vi ciia lop ma composite Ni-TiOi khi thay doi mat do dong dien: 2A/dm", 3A/dm"
5A/dm^ 7A/dm- nhiet do ma 40°C, tdc do khuSy 210 v/p.
Lan do 1 2 3 Trung binh
Ni 154 184 170 170
Ni-TiOj 2A/dm^
270 300 290 286
Ni-Ti02 3A/dm^
300 350 300 316
Ni-TiO, 5 A/dm-
225 240 230 230
Ni-Ti02 7A/dm^
270 260 290 273
Bang 7. Do ciing te vi ciia lop ma composite Ni-TiO: klii thay doi nhiet do ma: 35°C, 40°C, 45°C, toe do khuay 210 v/p, mat do dong dien 5 A/dm".
Lan do 1
2 : .1-:, 3
Trung binh
Ni 154 184 170 170
Ni-Ti02 30°C
270 260 250 260
Ni-Ti02 35°C
330 380 330 346
Ni-Ti02 40°C
225 240 230 230
Ni-TiO, 45°C
300 350 300 316 b. Lap mg composite Ni-Ti02
Cac ket qua do do cung te vi HV|o ddi vdi Idp ma composite AI2O3, Ti02 cho thay tdc do khuay, mat dp ddng dien va nhiet do dung dich ma cd anh hud-ng dang ke tdi dp cirng te vi ciia Idp ma composite.
PHAN TICH KET QUA
Tu- cac ket qua thi nghiem cho thay anh hudng cua tdc dp khuay den dp ciing te vi ciia Idp ma composite la dang ke tuy nhien miic dp anh hudng la khac nhau.
Anh hirdng ciia tdc khuay, vdi Idp ma Ni- AI2O3, khi tang tdc dp khuAy tii- 140 v/p dp
Phan Quang The vd cs Tap chi KHOA HOC & CONG NGHE 78(02): 3 - 7 Cling tang dan tu HV]o=218, dat cue dai tai
tdc dp 245 v/p vdi HV|o= 303 sau dd giam den HV|o=240 tai toe dp khuAy 312 v/p. Vdi lap ma Ni-Ti02, khi tang tdc dp khuay tu 140 v/p dp cung tang tu HV|o=232. dat cue dai tai tdc dp 175 v/p vdi HVio=243 sau dd giam den HV,0=191 tai tdc dp khuAy 245 v/p (Hinh 1).
Anh hudng ciia mat dp ddng dien, vdi Idp ma Ni-Al203, klii tang mat do ddng dien tii' 3A/dm" den 7A/dm" do cirng tang tu' HV|o=206 dat gia tri cue dai HV|o=273 tai mat do ddng dien 5A/dm" sau dd giam den gia tri HVio=190. Vdi Idp ma Ni-TiO^, do ciing te vi dat gia tri cue dai HVio=316 tai mat dp ddng dien 3 A/dm" va giam den HV]o=273 tai mat do ddng dien 7A/dm" (Hinh 2).
Ve anh hudng cua nhiet do, ddi vdi Idp ma Ni-ALOs, trong dai nhiet do tir 35°C den 50°C, do Cling te vi dat gia tri cue dai HV|o=383 tai nhiet do 45°C. Tuy nhien vdi Idp ma Ni-Ti02, do ciing te vi dat gia tri circ dai HV|o=346 tai nhiet dp 35°C (Hinh 3).
Cac ket qua tbi nghiem cho thay anh hudng ciia nhiet dp ma den dp ciing te vi la Idn nhat, thay ddi nhiet do trong khoang ndi tren cd the tang do Cling len 125% ddi vdi lap ma Ni- AI2O3 va 104% ddi vdi lop ma Ni-Ti02. Doi vdi Idp ma Ni-Al203, anh hudng ciia tdc do khuay den do cii-ng te vi Idn hon cua mat do ddng dien (78% va 43% vdi lap ma Ti02).
Tuy nhien, ddi vdi Idp ma Ni-Ti02, anh hudng cua mat do ddng dien den dp ciing te vi Idn ban anb budng ciia tdc dp khuay (86%
^a 60% ddi vdi Idp ma AI2O3).
0 300 X 250 '=• 200
= 150 c
•5 100 0 ' 50
0
0 6 cu'ng te vi l a p m a c o m p o s i t e p h u t h u o c toe d o k h u ^ y
A - - " " ^ ^ ~ ^
/ ^ ^ ' - • . ^
* " " " " * "--^ ~~*
140 \/p 175 \/p 210 \/p 245 \/p 278 \<p 312 \*p T6c do khu^y
- » - N i - A I 2 0 3
^ » - N i - ' n 0 2
Hinh 1. Moi quan he giua do ciing te vi cua lop ma composite va toe do khuay
Do cipng te vi lop ma composite phu thuoc vao mat do dong dien
-Ni-AI203 -Ni-Ti02
3A/dm2 5A/dm2 Mat do dong dien
Hinh 2. Moi quan he giiJa do ciing te vi cua lop ma composite va mat do dong dien
Do cipng te vi lap ma composite phu thuoc vao nhiet do
30 (Jo C 35 dp C 40 (Jo C Nhiet d6
45 (Jo C 50 do C
Hinh 3: Moi quan he giua do ciing te vi ,j ciia lop ma composite va nhiet do ma i Dp Cling te vi ciia Idp ma composite tang len the hien sir tham gia nhieu hon ciia cac hat trung tinh vao Idp ma. Do dp ciing te vi cua Idp ma cd lien he mat thiet vdi mat dp cac hat trung tinh tham gia vao Idp ma nen cd the sir dung ket qua do dp cung te vi ciia Idp ma de danh gia mat dp cae hat trung tinh tham gia vao lop ma. Trong mpt sd nghien cuu trudc day toe dp khuay la thong sd anh hudng manh den mat dp eac hat trung tinh tham gia vao Idp ma do tac dung duy tri cae hat trung tinh vdi mat dp cao lo' lung sat be mat ciia cathode [2,3]. Mat dp ddng dien it anh hudng tdi mat dp cac hat tham gia vao lap ma hon va sau do la nhiet dp, dp pH [4,5]. Cac ket qua nghien ciiu cho thay anh hudng ciia nhiet dp tdi do Cling te vi eiia Idp ma la Idn nh4t (cd the tang dp Cling Ciia Idp ma ALO., len tdi 125%), sau do den mat do ddng dien va nhiet dp ma. Tuy nhien anh hudng ciia cac thdng so ndi tren den dp Cling te vi la khac nhau doi vdi cac lap ma composite khac nhau tren nen Ni (miic dp anh
Phan Quang Thi vd cs Tap chi KHOA HOC & CONG NGHE 78(02): 3 - 7 hudng ciia ciing mdt thdng sd nhu mat dp ddng
dien cd the chenh lech tdi 34%). Su khac nhau giira cac ket qua nghien cuu trudc day ve tinh chat cua Idp ma composite so vdi nghien cuu nay cd the la do sir khac nhau cua tung he ma composite cu the. Anh hudng cua dp pH den dp Cling te vi la khdng dang ke nen do pH dugc giij bang hang sd trong nghien ciiu nay.
KET LUAN
De tang kha nang chdng mdn ciia be mat tiep xiic lam viec trong mdi trudng an mdn, tang dp Cling te vi ciia lap be mat la mdt giai phap huu hieu. Thay ddi cac thdng sd ciia qua trinh ma nhu tdc dp khuay, mat do ddng dien, nhiet dp ma dan den nhung thay ddi dang ke ve dp Cling te vi ciia Idp ma composite Ni-Al203 va Ni-Ti02. Nhiet dp cd anh hudng Idn nhat den dp Cling te vi cua lap ma composite (cd the tang dp cung den 125%) sau dd la tdc dp khuay va mat dp ddng dien (cd the tang dp Cling den 86%). Day la nhung ket qua cd y
nghTa to Idn trong viec nang cao kha nang chdng mdn cua be mat tiep xiic.
TAI LIEU THAM KHAO
[I].Indira Rajagopal., "Composite Coatings", Surface Modification Technologies"' Marcel Dekker, Inc, New York, 1989.
[2].Hovestad. A, Janssen. L.J.J., Electrochemical Co-deposition of Inert Particles in a Metallic Matrix, Journal of Applied Electrochemistry. Vol.
25,pp. 519-527, (1995).
\}\R. C. Agarwala and Vljaya Aganvala;
Eleetroless alloy/composite coatings: A review;
Sadhana Vol. 28, Parts 3 & 4^ pp.475-493, June/August 2003.
[4].Gang Wu, Nlng Ll, Derul Zhou, Kurachl Mlisuo; Eleetrodeposited Co-Ni-Al203 composite coatings; Surface and Coatings Technology, 176,
157-164,2004.
[5].Hovestad. A, Janssen. L.J.J., Electrochemical Codeposition of Inert Particles in a Metallic Matrix, Journal of Applied Electrochemistry, Vol.
25, pp. 519-527, (1995).
ABSTRACT
EFFECTS OF PROCESS PARAMETERS
ON THE MICRO-HARDNESS OF COMPOSITE COATINGS
Phan Quang The*, Nguyen Dang Binh, Tran Minh Due, Ly Viet Anh
Thai Nguyen University of Technology - TNU
One of the solutions to enhance the wear resistance of the composite coatings layer based on Nickel matrix. The research resuhs of Ni-ALOjand Ti-Ti02showed that the micro-hardness of the composite coating depends considerably on mixing velocity, current density and the temperature of electrolyze. The variation of these parameters in electroplating process can produce the composite coating with the micro-hardness increasing more than 2 times compared with normal Ni coating layer.
Key words: Composite Coaling; Nl-AhOj; Composite process Parameters; Mixing velocity;
Micro-hardness
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