ZrO 2?Al 2O 3陶瓷涂层耐蚀性能研究
中南大学材料科学与工程系(长沙410083) 马正青 黎文献 谭敦强 肖于德
[摘 要] 用溶胶2凝胶(s ol 2gel )法在不锈钢表面制备xZ rO 2?yAl 2O 3陶瓷涂层。用X 射线衍射(XRD )和扫描电子显微
镜能谱仪分析了涂层组成与结构;用金相显微镜观测了涂层的孔隙率;用浸泡法和高温抗氧化性试验研究了涂层的耐腐蚀性能。结果表明:xZ rO 2?yAl 2O 3涂层随二组分含量的趋近,结构从晶态转变成微晶与玻璃态混合组成,直至完全的玻璃化,涂层致密度提高,耐高温和耐腐蚀性能依次增强。
[关键词] 耐蚀性; 陶瓷涂层; Z rO 2?Al 2O 3; 溶胶2凝胶法
[中图分类号] TG 174.453 [文献标识码] A [文章编号] 1001-1560(2001)08-0014-02
[收稿日期] 2001-03-07
1 前 言
Z rO 2?Al 2O 3复合陶瓷具有优良的化学稳定性和热稳定性,广
泛用于金属或器件的表面保护。涂层的制备采用料浆喷涂2烧结法、粉末高温喷射法和物理气相沉积法[1～4],其中溶胶2凝胶法制备薄膜和涂层材料更显其优势,90年代相继出现大量的文献报道[5～8]。
本研究用溶胶2凝胶法制备了不同配比的xZ rO 2?yAl 2O 3陶瓷涂层,并探讨了其组成、结构对耐蚀性能的影响。
2 实验方法
将一定比例的Al (NO 3)3?9H 2O 和Z rOCl 2?8H 2O 溶于无水乙醇,加入适量的乙二醇、水和催化剂,室温水解,形成均匀的溶胶,陈化后制成凝胶。
基材为1828不锈钢,尺寸为20×30×2。经除油、酸蚀、氧化预处理,清洗后浸入上述凝胶,在基材表面形成凝胶膜,放入100℃干燥箱中干燥后,放置在空气炉中以15℃/min 升温速率升至
750℃,保温3h ,即可烧结成陶瓷涂层。
用X 射线衍射(XRD )和扫描电子显微镜(SE M )分析涂层的组成与结构;用差重法测试涂层的高温氧化速率,并求出保护系数P (P =基材的氧化速率/涂层试片的氧化速率);用浸泡试验测试涂层在10%H 2S O 4溶液中的耐腐蚀性能。
3 结果与讨论
3.1 组成与结构
根据XRD 和SE M 实验结果,所制备的xZ rO 2?yAl 2O 3陶瓷涂层结构随涂层组成成分而变化。单组分的Z rO 2(B )或Al 2O 3(F )涂层为明显的晶态结构,复合组分的70Z rO 2?30Al 2O 3(C )和30Z rO 2?
70Al 2O 3(E )涂层为微晶与玻璃态的混合结构,等体积分数组成的Z rO 2?Al 2O 3(D )为玻璃态结构(见图1)
。
3.2 孔隙率
用金相显微镜观测的涂层单位面积上的气孔数目,结果见表1。可见,晶态组成的单组分Z rO 2或Al 2O 3涂层,由于烧结过程中晶粒生长过快,气体不能及时排出,涂层孔隙率较大;复合涂层在烧结过程中,Al 2O 3与Z rO 2相互抑制了晶粒的生长,晶粒细小,气体充分排出,使得涂层孔隙率大为降低。
表1 涂层孔隙率
涂层
组成Z rO 270Z rO 2?30Al 2O 350Z rO 2?50Al 2O 330Z rO 2?
70Al 2O 3Al 2O 3
1828
不锈钢
孔隙率
(%)
0.65
0.40
0.15
0.50
0.85
-
3.3 高温抗氧化性
1828不锈钢空白试片的氧化增重速率大,高温抗氧化能力
差。涂有xZ rO 2?yAl 2O 3陶瓷涂层的试片,氧化增重速率较慢,保护系数大,高温抗氧化性能好,且单组分Z rO 2涂层抗氧化能力优于单组分Al 2O 3涂层,复合涂层高温抗氧能力比单组分涂层好,且随涂层中二组分含量的趋近,高温抗氧化能力增强(见表2)。
14
M aterials
Protection
Study on C orrosion Resistance of ZrO 2?Al 2O 3Ceramic C oating
Aug.2001
V ol.34N o.8
这与涂层的结构和致密度的变化相一致。
表2 涂层高温(850℃)氧化速率(mg/cm 2?min)
时间(h )
Z rO 2
(B )
70Z rO 2?30Al 2O 3(C )50Z rO 2?50Al 2O 3(D )30Z rO 2?70Al 2O 3
(E )Al 2O 3
(F )1828
不锈钢(G )2 0.035 0.024 0.012 0.030 0.050 0.100
40.0580.0340.0160.0500.0700.15060.0700.0420.0210.0600.0900.18090.0760.0460.0230.6500.1000.20012
0.090
0.0520.0260.0680.1100.230
平均保护系数 2.6 4.4
9.0
3.1
2.0
-
3.4 耐腐蚀性
先称量涂层试片和空白试片的质量(W 1),并测定各试片表面积(S ),然后浸挂在10%H 2S O 4介质中,浸泡一定时间(t )后,取出,清洗、干燥,再称量各试片的质量(W 2),计算腐蚀失重速率
V =(W 2-W 1)/S ?t ,结果见图2。
由图2可见,各试片的腐蚀失重速率随着浸泡时间的延长而加快,空白试片失重速率大于涂层试片,且不同涂层试片在相同的浸泡时间里腐蚀速率随涂层中组分含量的趋近而减少,等体积分数的玻璃态Z rO 2?Al 2O 3涂层在10%H 2S O 4介质中具有优良的耐蚀性能。这表明该陶瓷涂层具有较好的抗硫酸腐蚀能力;当涂层致密度较小时,腐蚀介质易通过孔隙渗透到基体表面,使基材腐蚀溶解,并在界面发生各种化学反应,造成陶瓷涂层脱落出现腐蚀坑,因此,陶瓷涂层随组成含量的趋近孔隙率降低,致密度提高,腐蚀失重速度降低,耐腐蚀能力增强[9～12]。
4 结 论
(1)采用溶胶2凝胶法制得的xZ rO 2?yAl 2O 3陶瓷涂层,随二组
分成分的趋近致密度增加,结构由晶态向玻璃态转变。
(2)溶胶2凝胶法制备的陶瓷涂层可提高不锈钢耐硫酸腐蚀
性能和高温抗氧化性能,非晶态结构的Z rO 2?Al 2O 3陶瓷涂层具有较好的耐蚀性能。
[
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材料保护ZrO 2?Al 2O 3
陶瓷涂层耐蚀性能研究
2001年8月
第34卷第8期
15
Journal of Materials Protection
(M onthly,Started in1960)
ISS N1001-1560August2001Vol.34No.8Serial No.271
C ontents&Abstracts
Evolution of I nnocuous and N on2Pollution E lectroplating
T U Zhen2mi,ZH ANGJing2shuang,Y ANG Zhe2long(Harbin Institute of T echnology ,Harbin,P.R.China150001).Cailiao Baohu2001,34(8),01～04(Ch).The study and application of cyanide free,cyanogens and lead free,chrome replaced, cadmium replaced electroplating were detailed for there exist s ome harm ful and toxic chemicals in comm on electroplating s olutions,such as CN-,F2,Cd2+,Pb2+,Cr6+ etc.Properties of electroplated coatings were com pared.The measures for prom oting continuous clean production of electroplating were put forward based on the concrete situation in China.
Metalization on Advanced N on2Organic M aterial———Z nO Thin Film T echnol2 ogy
SHE N W ei,PE NG De2quan,SHE N X iao2dan(Wuhan Research Institute of M ateri2 als Protection,Wuhan,P.R.China430030).Cailiao Baohu2001,34(8),05～07 (Ch).ZnO thin film technology has been reviewed.A high adhesive strength(≥25 N/mm2)of electroless metal deposits on the very sm ooth(Ra≤0.01μm)non2or2 ganic material substrate was obtained by taking ZnO thin film as the intermediate lay2 er which was prepared by spray pyrolysis method.The photocatalytic reaction of ZnO thin film makes it possible to develop a new,full additive2based process in printed circuit board(PC B)fabrication.The preparation and properties of ZnO film,metal2 ization processes and the interface analysis results have been introduced at present paper.
Advances on Corrosion C aused by Sulfate2R educing B acteria
LIU Jing,H OU Bao-li,ZHE NG Jia2shen et al(Chemistry Department,Huazhong University of Science and T echnology,Wuhan.P.R.China430074).Cailiao Bao2 hu2001,34(8),08～11(Ch).Sulfate2reducing bacteria(SRB)is one of the m ost im portant microorganisms in microbiologically in fluenced corrosion(MIC)in oil field water injection system and cycle cooling water system in industry.The harms of SRB corrosion have received much attention in the latest twenty years.The SRB corrosion is characterized by formation of biofilms on metal surfaces,which have changed the corrosion conditions such as pH value,diss olved oxygen,chemical species and con2 tents.The metabolite of SRB interacted with metal substrate and accelerated the cor2 rosion of metal and alloy.The paper covers the following topics:microbiological physidogy,SRB corrosion mechanism,SRB corrosion on different materials,measur2 ing methods and control of SRB corrosion.Recent advances on MIC and the trends were introduced.
I nfluence of Low2E nergy Ion B eams Bomb ardment on Microstructure and Properties of Amorphous N i2P Film
ZE NG Peng,H U She2jun,XIE G uang2rong et al(C ollege of M aterials and Energy S ource,G uangdong University of T echnology,G uangzhou,P.R.China510643). Cailiao Baohu2001,34(8),12～13(Ch).The in fluence of the low2energy nitrogen ion bombardment on crystallization of am orphous Ni2P alloy film and the microstruc2 ture and microhardness of the films were investigated by means of XRD,AES,EP2 M A,DSC and ultramicrohardness tester.The results showed that Ni and Ni3P phases were separated out in the film and priority orientation was appeared on crystal face during the bombardment of nitrogen ion beam at3.0～4.0keV and80～200mA. The crystallization tem perature of am orphous Ni2P alloy film decreased with the in2 crease of bombardment energy and current of nitrogen ion beam.The in fluence of ion beam current on crystallization tem perature was greater than that of accelerated v olt2 age.Because of the effect of energy particles on the am orphous films,ion im planta2 tion action was produced and nitrogen content in the surface was increased.The in2 crease of microhardness of the films reduced with the increase of ion beam current. The microhardness increased obviously with the increase of the accelerated v oltage of nitrogen ion.E ffected by the nitrogen ion bombardment at4000V accelerated v olt2 age,the microhardness of the films reached H V2131which is increased obviously than that obtained by normal annealing.
Study on Corrosion R esistance of Z rO2?A l2O3Ceramic Coating
M A Zheng2qing,LI W en2xian,T AN Dun2qiang et al(Department of M aterial and Engineering,Central S outh University,Changsha,P.R.China410083).Cailiao Baohu2001,34(8),14～15(Ch).The preparation of xZ rO2?yAl2O3ceramic coat2 ing on stainless steels surface by s ol2gel was studied.The coating com position and structure were analyzed by XRD and SE M.The coating porosity was observed by metallurgical microscope.The corrosion resistance of ceramic coating was examined by immersion and high tem perature oxygen2resistance experiment.The results showed that the structure truned from crystal to non2crystal when the content of the com posi2 tion of xZ rO2?yAl2O3tended to the same.The porosity and corrosion resistance of the coating were im proved.
Wearability of H igh Chromium C ast I ron at S and Slurry Wear Condition
W ANG Xuan2guo,Y AN X2ping(Institute of Reliability,Wuhan University of Sci2 ence and T echnology,Wuhan,P.R.China430063).Cailiao Baohu2001,34(8), 16～18(Ch).T ests of several high chromium cast iron sam ples were made by self2 regulating sand slurry wear test machine.W earability of the sam ples was measured and the microstructures were observed by SE M.The in fluence of form and distribu2 tion of carbide,base structure and rare earth treatment on wear2resistance of high chromium cast irons was analysed at sand slurry condition.The resluts show that the form and distribution of carbide have great in fluence on wearability of high chromium cast iron.Bolck or short shaft shape and uniformly distributed carbides contribute to the https://www.doczj.com/doc/fd1163453.html, or long needle shape carbides are not beneficial to the wear re2 sistance.The wearability can be im proved by increasing microhardness of base struc2 ture and bond strength of base structure and carbides.The addition of rare earth ele2 ments can als o im prove the wear resistance of the high chromium cast irons at sand slurry wear condition.
Study on I nducing Process of E lectroless N i2P A lloy P lating on B raze and B rass Substrates
ZH ANG Chao2yang,WEI X i2wen,LI Bing et al(Institute of Chemical M aterials, China Academy of Engineering Physics,M ianyang,P.R.China621900).Cailiao Baohu2001,34(8),19～20(Ch).E lectroless Ni2P alloy plating on braze or brass surface needs a inducing process.The process was studied with cathode current and with touch of active metal in the bath.The results indicated that inducing process of electroless Ni2P alloy plating on braze or brass surface is a electrochemical process, that is Ni2+which has been ads orbed on substrate surface changed into Ni and de2 posited on the su face after gaining electrons,then self2catalytic reaction went on con2 tinously and automaticlly.It was shown that there was a electrochemical process in electroless Ni2P plating reaction,when brass plates plated with Ni2P alloy were taken as inducing materials.In addition,brass can not induce spontaneously electroless nickel plating reaction and the relevant experiments and deduction showed the cor2 rectness that a“electrons share”trend existed in brass.
C arbon2Steel Corrosion B eh avior in C l-H ydrosolvent at H igh T emperature LI Jing2ping,LOU T ai2fang et al(Chemistry and M olecular Science C ollege,Wuhan University,Wuhan,P.R.China430072).Cailiao Baohu2001,34(8),21～22 (Ch).
Development and Design of Multi2Function Pow er
ZH ANG Y u2feng(Wuhan Ordnance N oncommissioned O fficer School,Wuhan,P.R. China430064).Cailiao Baohu2001,34(8),23～24(Ch).A multi2function pow2 er inverter for welding,brush plating and charging was developed.E lectrodeposition during brush plating could be changed at a broad area with the inverter by controlling wave,frequency,pass and close and average value of electric current.E lectrodepo2 sition process of metal ion was changed and brush plating coating with fine grain, high hardness and g ood wear resistance was obtained.PW M microelectronic control technique and AC2DC2AC2DC invert technique with M OSFET half bridge inverter of high frequency and high power were used as main circuit control of im pulse preset and feedback was used as im pulse circuit.The external characteristic was designed as out2extension.The power inverter was characterized by high reliability,high effi2 cency and small size.