热处理对等离子喷涂WC-12Co涂层性能的影响
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摘要
为了提高等离子喷涂WC-12Co涂层的性能,分别对其进行了500、650、800和950℃保温60 min的真空热处理。利用威布尔统计方法对涂层的显微硬度进行分析,利用X射线衍射仪(XRD)、扫描电镜(SEM)和能谱仪(EDS)对热处理前后WC-12Co涂层组织结构进行表征,采用自制的干砂型常温冲刷磨损试验机对WC-12Co涂层热处理前后的抗冲蚀磨损性能进行探讨。结果表明:热处理温度为950℃时,涂层中出现大量Co_6W_6C相,在距离涂层表面0～100μm左右的区域内,涂层较为疏松,涂层显微硬度较低且变化较大,在距离涂层表面100～300μm的区域内涂层硬度趋于稳定且较高,同时,涂层的冲蚀磨损量最好,为0.1124 mg/mm~2,较喷涂态WC-12Co涂层的冲蚀磨损量减少41.88%。当热处理温度为800℃时,weibull模量和特征显微硬度最大,分别为11.8426 HV和1411.3 HV,涂层显微硬度的分散性低、可靠性高,涂层质量相对较为稳定。随着真空热处理温度升高,涂层的主要组成相由WC、W_2C转变为Co_3W_3C和Co_6W_6C。真空热处理后,涂层中各元素都发生了不同程度的扩散,其中Al元素扩散程度最大。
In order to improve the performance of plasma sprayed WC-12 Co coatings, vacuum heat treatment was carried out at 500 ℃, 650 ℃, 800 ℃ and 950 ℃ for 60 min. Microhardness of the coatings was analyzed by Weibull statistics, and microstructure of the WC-12 Co coating before and after heat treatment was characterized by means of X-ray diffractometer(XRD), scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS) analysis. The erosion wear resistance of the WC-12 Co coating before and after heat treatment was studied by using a self-made dry sand mold erosion wear tester at room temperature. The results show that when the heat treatment temperature is 950 ℃, a large number of Co_6W_6C phases appear in the coating layer. At the distance of 0 μm to 100 μm from the coating surface, the coating is looser, the microhardness of the coating is low and varied greatly, and the hardness of the coating tends to be stable and high in the range of 100 μm to 300 μm from the coating surface. At the same time, the erosion wear mass loss of the coating is the least(0.1124 mg/mm~2), which is 41.88% less than that of the sprayed WC-12 Co coating. When the heat treatment temperature is 800 ℃, the weibull modulus and the characteristic microhardness of the coating are the largest, which are 11.8426 HV and 1411.3 HV, respectively, and the microhardness has a low dispersion and a high reliability, and the quality of the coatings is relatively stable. With the increase of the vacuum heat treatment temperature, the main phase of the coating is transformed from WC and W_2C to Co_3W_3C and Co_6W_6C. After vacuum heat treatment, all the elements in the coating are diffused to different degrees, and the diffusion degree of Al element is the largest.
In order to improve the performance of plasma sprayed WC-12 Co coatings, vacuum heat treatment was carried out at 500 ℃, 650 ℃, 800 ℃ and 950 ℃ for 60 min. Microhardness of the coatings was analyzed by Weibull statistics, and microstructure of the WC-12 Co coating before and after heat treatment was characterized by means of X-ray diffractometer(XRD), scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS) analysis. The erosion wear resistance of the WC-12 Co coating before and after heat treatment was studied by using a self-made dry sand mold erosion wear tester at room temperature. The results show that when the heat treatment temperature is 950 ℃, a large number of Co_6W_6C phases appear in the coating layer. At the distance of 0 μm to 100 μm from the coating surface, the coating is looser, the microhardness of the coating is low and varied greatly, and the hardness of the coating tends to be stable and high in the range of 100 μm to 300 μm from the coating surface. At the same time, the erosion wear mass loss of the coating is the least(0.1124 mg/mm~2), which is 41.88% less than that of the sprayed WC-12 Co coating. When the heat treatment temperature is 800 ℃, the weibull modulus and the characteristic microhardness of the coating are the largest, which are 11.8426 HV and 1411.3 HV, respectively, and the microhardness has a low dispersion and a high reliability, and the quality of the coatings is relatively stable. With the increase of the vacuum heat treatment temperature, the main phase of the coating is transformed from WC and W_2C to Co_3W_3C and Co_6W_6C. After vacuum heat treatment, all the elements in the coating are diffused to different degrees, and the diffusion degree of Al element is the largest.
引文
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[13] 毛卫国,陈强,张斌,等.等离子喷涂热障涂层材料弹性模量与硬度的压痕测试分析[J].材料工程,2011(10):66-71+77.MAO Wei-guo,CHEN Qiang,ZHANG Bin,et al.Investgations of elastic modulus and hardness of air plasma sprayed thermal barrier coatings by nanoindentation method[J].Journal of Materials Engineering,2011(10):66-71+77.
[14] 毕恩兵,孙宏飞,王灿明,等.纳米陶瓷等离子喷涂层显微硬度的weibull分布及与涂层组构的对应特性[J].材料保护,2012,45 (5):24-27.BI En-bing,SUN Hong-fei,WANG Can-ming,et al.Weibull distribution of microhardness of plasma sprayed nanostructured ceramic coating and relation between phase composition and microhardness[J].Journal of Materials Protection,2012,45(5):24-27.
[15] Ghadami F,Sohi M H,Ghadami S.Effect of bond coat and post-heat treatment on the adhesion of air plasma sprayed WC-Co coatings[J].Surface and Coatings Technology,2014,261(11):289-292.
[16] Sohi M H,Khameneh S A,Hokamoto K A.DTA study on HVOF thermally sprayed WC-M coatings[J].Journal Materials Science Forum,2007,566(1):155-160.
[17] Sunny Z,Apurbba K S.Microstructure and wear performance of heat treated WC-12Co microwave clad[J].Vacuum,2016,131(6):213-217.
[2] 梁存光,李新梅,张鹏飞.等离子喷涂WC-12Co涂层抗冲刷磨损行为[J].表面技术,2017,46(9):7-12.LIANG Cun-guang,LI Xin-mei,ZHANG Peng-fei.Erosion wear behavior of WC-12Co coatings prepared by APS[J].Surface Technology,2017,46(9):7-12.
[3] 孙万昌,张峰,张佩,等.热处理对HVOF WC-17Co 涂层组织结构及耐磨性能的影响[J].煤炭学报,2015,40(2):476-480.SUN Wan-chang,ZHANG Feng,ZHANG Pei,et al.Influence of heat treatment on microstructure and wear resistance of HVOF WC-17Co coatings[J].Journal of China Coal Society,2015,40(2):476-480.
[4] 赵坚,陈小明,吴燕明,等.热处理对超音速火焰喷涂WC涂层微观结构及性能的影响[J].兵器材料科学与工程,2017,40(2):100-104.ZHAO Jian,CHEN Xiao-ming,WU Yan-ming,et al.Effect of heat treatment on microstructure and properties of high velocity sprayed WC coatings[J].Ordnance Material Science and Engineering,2017,40(2):100-104.
[5] Asl S K,Sohi M H,Hokamoto K,et al.Effect of heat treatment on wear behavior of HVOF thermally sprayed WC-Co coatings[J].Wear,2006,260:1203-1208.
[6] Zhe G,Si H H,Gao L S,et al.Tribological behaviour at various temperatures of WC-Co coatings prepared using different thermal spraying techniques[J].Tribology International,2016,104:36-44.
[7] Farzin G,Soheil G,Hassan A P.Structural and oxidation behavior of atmospheric heat treated plasma sprayed WC-Co coatings[J].Vacuum,2013,94:64-68.
[8] 董艳春,阎殿然,张建新,等.热处理温度对纳米TiN涂层组织和性能的影响[J].稀有金属材料与工程,2013,42(8):1711-1714.DONG Yan-chun,YAN Dian-ran,ZHANG Jian-xin,et al.Influence of heat treatment temperature on the microstructure and properties of reactive plasma sprayed TiN nano-coatings[J].Rare Metal Materials and Engineering,2013,42(8):1711-1714.
[9] 陆晨光,阎殿然,董艳春,等.反应等离子喷涂TiN涂层热处理后力学性能研究[J].稀有金属材料与工程,2009,38(S1):129-132.LU Chen-guang,YAN Dian-ran,DONG Yan-chun,et al.Mechanical property of TiN coating prepared by reactive plasma spraying after heattreatment[J].Rare Metal Materials and Engineering,2009,38(S1):129-132.
[10] Ma N,Guo L,Cheng Z X,et al.Improvement on mechanical properties and wear resistance of HVOF sprayed WC-12Co coatings by optimizing feedstock structure[J].Applied Surface Science,2014,320:364-371.
[11] Wang G,Xing C,Tao F,et al.Enhancement in the corrosion resistance of WC coatings by adding a Fe-based alloy in simulated seawater[J].Surface and Coatings Technology,2016,305:62-66.
[12] Mutairia S A,Hashmia M S J,Yilbas B S,et al.Microstructural characterization of HVOF/plasma thermal spray of micro/nano WC-12%Co powders[J].Surface and Coatings Technology,2015,264:175-186.
[13] 毛卫国,陈强,张斌,等.等离子喷涂热障涂层材料弹性模量与硬度的压痕测试分析[J].材料工程,2011(10):66-71+77.MAO Wei-guo,CHEN Qiang,ZHANG Bin,et al.Investgations of elastic modulus and hardness of air plasma sprayed thermal barrier coatings by nanoindentation method[J].Journal of Materials Engineering,2011(10):66-71+77.
[14] 毕恩兵,孙宏飞,王灿明,等.纳米陶瓷等离子喷涂层显微硬度的weibull分布及与涂层组构的对应特性[J].材料保护,2012,45 (5):24-27.BI En-bing,SUN Hong-fei,WANG Can-ming,et al.Weibull distribution of microhardness of plasma sprayed nanostructured ceramic coating and relation between phase composition and microhardness[J].Journal of Materials Protection,2012,45(5):24-27.
[15] Ghadami F,Sohi M H,Ghadami S.Effect of bond coat and post-heat treatment on the adhesion of air plasma sprayed WC-Co coatings[J].Surface and Coatings Technology,2014,261(11):289-292.
[16] Sohi M H,Khameneh S A,Hokamoto K A.DTA study on HVOF thermally sprayed WC-M coatings[J].Journal Materials Science Forum,2007,566(1):155-160.
[17] Sunny Z,Apurbba K S.Microstructure and wear performance of heat treated WC-12Co microwave clad[J].Vacuum,2016,131(6):213-217.