抑制剂对WC-Co硬质合金涂层性能的影响

doi:10.15541/jim20160590

摘要/Abstract

摘要：

利用原位还原碳化反应合成的超细WC-12Co复合粉末作为原料, 分别添加1.0wt%晶粒长大抑制剂即VC、Cr₃C₂和NbC, 经团聚造粒和超音速火焰(HVOF)喷涂制备了超细结构的硬质合金涂层。研究了不同晶粒长大抑制剂对涂层的显微组织结构、物相、硬度、耐磨性能和耐蚀性能的影响。结果表明, 与未添加晶粒长大抑制剂涂层相比, 添加1.0wt% VC或Cr₃C₂制备的硬质合金涂层中WC颗粒的平均尺寸降低了约49%, 涂层硬度明显提高, 磨损速率降低了约52%~55%。添加1.0wt% NbC对制备涂层中WC颗粒尺寸的抑制作用不明显, Co粘结相中由于形成了(W, Nb)C化合物, 其耐蚀性获得显著提高, 但该化合物脆性大, 导致涂层耐磨性不及添加VC和Cr₃C₂制备的涂层。

关键词: 晶粒长大抑制剂, 超细WC-Co复合粉, 硬质合金涂层, 耐磨性, 耐蚀性

Abstract:

The ultrafine WC-12Co composite powder was synthesized by in situ reduction and carbonization reactions. Using the composite powder with an addition of 1.0wt% grain growth inhibitor (GGI) i.e. VC, Cr₃C₂ and NbC, as raw materials, the ultrafine-structured cemented carbide coatings were fabricated by the high velocity oxy-fuel (HVOF) spraying method. Prior to thermal spraying, the powders were agglomerated into thermal spray feedstock. The effects of GGI addition on phase constitution, microstructure, hardness, and wear and corrosion properties of the coatings were investigated. The results show that the mean WC particle size of coatings with an addition of 1.0wt% VC or Cr₃C₂ decreases by about 49% as compared to that without GGI. Moreover, hardness of the coatings is significantly improved and the wear rate decreases by 52%-55%. Addition of 1.0wt% NbC has little effect on WC particle size of the coating but leads to formation of (W, Nb)C compound in the Co binder. Thus the corrosion resistance of the coating containing NbC is significantly enhanced. However, its wear resistance is lower than those with VC or Cr₃C₂, due to high brittleness of the (W, Nb)C compound.

Key words: grain growth inhibitor, ultrafine WC-Co composite powder, cemented carbide coating, wear resistance, corrosion resistance

中图分类号:

TQ174

王学政, 王海滨, 刘雪梅, 杨涛, 宋晓艳. 抑制剂对WC-Co硬质合金涂层性能的影响[J]. 无机材料学报, 2017, 32(8): 813-818.

WANG Xue-Zheng, WANG Hai-Bin, LIU Xue-Mei, YANG Tao, SONG Xiao-Yan. Grain Growth Inhibitor on the WC-Co Cemented Carbide Coating[J]. Journal of Inorganic Materials, 2017, 32(8): 813-818.

图/表 11

表1 WC-12Co复合粉中晶粒长大抑制剂的添加量/wt%

Table 1 Contents of grain growth inhibitor in WC-12Co composite powder/wt%

Sample	VC	Cr₃C₂	NbC
N1	1	0	0
N2	0	1	0
N3	0	0	1
N4	0	0	0

表2 WC-12Co涂层喷涂工艺参数

Table 2 Spraying parameters of WC-12Co coating

Kerosene /GPH	Oxygen /SCFH	Distance /mm	Carrier gas /SCFH	Feed rate /(r·min^-1)
6.0	2000	340	25	5.5

图1 WC-12Co喷涂粉末(a)和涂层(b)的XRD图谱

Fig. 1 XRD patterns of WC-12Co spraying powder (a) and coating (b)

图2 WC-12Co涂层的SEM照片

Fig. 2 SEM microstructures of WC-12Co coating(a) Sample N1; (b) Sample N2; (c) Sample N3; (d) Sample N4

图3 WC-12Co涂层SEM显微组织及WC晶粒尺寸分布

Fig. 3 SEM microstructure and WC grain size distribution of WC-12Co coating(a) Sample N1; (b) Sample N2; (c) Sample N3; (d) Sample N4

表3 WC-12Co涂层的显微硬度

Table 3 Microhardness of WC-12Co coating

Sample	N1	N2	N3	N4
Microhardness HV_0.3	1313±64	1283±65	1175±99	1120±88

图4 WC-12Co涂层磨损速率

Fig. 4 Wear rate curve of WC-12Co coating

图5 涂层划痕的SEM照片

Fig. 5 SEM images of coating scratch(a) (b) Sample N1; (c) (d) Sample N4

图6 WC-12Co涂层的塔菲尔曲线和电化学交流阻抗图谱

Fig. 6 Tafel curves and EIS curves of WC-12Co coatings

表4 WC-12Co涂层的腐蚀电位Ecorr和腐蚀电流Icorr

Table 4 Corrosion potentials (Ecorr) and current densities (Icorr) of WC-12Co coating

Sample	N1	N2	N3	N4
E_corr /V	-0.42	-0.47	-0.32	-0.47
I_corr/(A•cm^-2)	1.109×10^-5	2.371×10^-5	3.981×10^-6	8.913×10^-5

图7 添加NbC的WC-12Co涂层的SEM照片(a)和相应位置的EDS分析结果(b)

Fig. 7 EDS analysis of the WC-12Co coating with addition of NbC

参考文献 27

[1]	TKADLETZ MICHAEL, SCHALK NINA, DANIEL ROSTISLAV, et al.Advanced characterization methods for wear resistant hard coatings: A review on recent progress.Surf. Coat. Technol., 2016, 285: 31-46.
[2]	BERGER LUTZ-MICHAEL.Application of hardmetals as thermal spray coatings.Int. J. Refract. Met. Hard Mater., 2015, 49: 350-364.
[3]	DING ZHANG-XIONG, WAN WEN-CHEN, ZHAO HUI, et al.Research progress and prospect of WC-Co composite coatings prepared by thermal spraying.J. Therm. Spray Technol., 2012, 4(2): 1-5.
[4]	RAJINIKANTH V, VENKATESWARLU K.An investigation of sliding wear behaviour of WC-Co coating. Tribol. Int., 2011, 44(12): 1711-1719.
[5]	YUAN JIAN-HUI, MA CHUN-WEI, YANG SHANG-LEI, et al.Improving the wear resistance of HVOF sprayed WC-Co coatings by adding submicron-sized WC particles at the splats' interfaces .Surf. Coat. Technol., 2016, 285: 17-23.
[6]	ANTONOV M, VEINTHAL R, YUNG D L, et al. Mapping of impact-abrasive wear performance of WC-Co cemented carbides. Wear, 2015, 332-333: 971-978.
[7]	ESPINOSA-FERNÁNDEZ L, BORRELL A, SALVADOR M D, et al. Sliding wear behavior of WC-Co-Cr3C2-VC composites fabricated by conventional and non-conventional techniques.Wear, 2013, 307(1/2): 60-67.
[8]	SONG XIAO-YAN.Low-cost & short-term preparation and applications of ultrafine and nano-scaled WC-Co composite powders.China Tungsten Industry, 2010, 25(3): 19-23.
[9]	ZHOU KE-SONG, DENG CHUN-MING, LIU MIN, et al.Characterizations of fatigue and salt spray corrosion resistance of hvaf sprayed WC-17Co and WC-10Co4Cr coatings on the substrate of 300M Steel.Rare Met. Mater. Eng., 2009, 38(4): 671-676.
[10]	FU JUN, SONG XIAO-YAN, WEI CHONG-BIN, et al.Effect of combined addition of grain growth inhibitors on the cemented carbides prepared by WC-Co composite powder. Rare Met. Mater. Eng., 2014, 43(8): 1928-1934.
[11]	SUGIYAMA I, MIZUMUKAI Y, TANIUCHI T, et al.Three-dimensional morphology of (W,V)Cx in VC-doped WC-Co hard metals.Scr. Mater., 2013, 69(6): 473-476.
[12]	CHEN HUI, LUAN DAO-CHENG, WANG ZHENG-YUN, et al.Effects of inhibitors on the properties of ultra fine WC-Co cemented carbide. China Tungsten Industry, 2011, 26(1): 34-37.
[13]	LIN NAN, HE YUE-HUI, WU CHONG-HU, et al.Fabrication of tungsten carbide-vanadium carbide core-shell structure powders and their application as an inhibitor for the sintering of cemented carbides.Scr. Mater., 2012, 67(10): 826-829.
[14]	BONACHE V, SALVADOR M D, FERNÁNDEZ A, et al. Fabrication of full density near-nanostructured cemented carbides by combination of VC/Cr3C2 addition and consolidation by SPS and HIP technologies.Int. J. Refract. Met. Hard Mater., 2011, 29(2): 202-208.
[15]	XIAO DAI-HONG, HE YUE-HUI, LUO WEI-HONG, et al.Effect of VC and NbC additions on microstructure and properties of ultrafine WC-10Co cemented carbides.Trans. Nonferrous Met. Soc. China, 2009, 19(6): 1520-1525.
[16]	HUANG S G, LI L, VANMEENSEL K, et al.Cr3C2 and NbC doped WC-Co cemented carbides prepared by pulsed electric current sintering.Int. J. Refract. Met. Hard Mater., 2007, 25(5): 417-422.
[17]	BAN Z G., SHAW L L.Characterization of thermal sprayed nanostructured WC-Co coatings derived from nanocrystalline WC-18wt%Co powders. J. Therm. Spray Technol., 2003, 12(1): 112-119.
[18]	WANG QUN, ZHANG SHI-YING, CHENG YING-LIANG, et al.Wear and corrosion performance of WC-10Co4Cr coatings deposited by different HVOF and HVAF spraying processes.Surf. Coat. Technol., 2013, 218(1): 127-136.
[19]	LI XIAO-FENG, LIU YONG, WEI WEI, et al.Influence of NbC and VC on microstructures and mechanical properties of WC-Co functionally graded cemented carbides.Mater. Des., 2016, 90: 562-567.
[20]	KE DE-QING, PAN YING-JUN, LU XU-FENG, et al.Influence and effectivity of Sm2O3 and Cr3C2 grain growth inhibitors on sintering of WCoB-TiC based cermets.Ceram. Int., 2015, 41(10): 15235-15240.
[21]	AL-AQEELI N, SAHEB N, LAOUI T, et al.VC and Cr3C2 doped WC-based nano-cermets prepared by MA and SPS.Ceram. Int., 2014, 40: 11759-11765.
[22]	OUYANG CHEN-XIN, ZHU SHI-GEN, LI D Y.Corrosion and corrosive wear behavior of WC-MgO composites with and without grain-growth inhibitors.Journal of Alloys and Compounds, 2014, 615: 146-155.
[23]	HONG SHENG, WU YU-PING, ZHENG YU-GUI, et al.Microstructure and electrochemical properties of nanostructured WC-10Co-4Cr coating prepared by HVOF spraying. Surf. Coat. Technol., 2013, 235(22): 582-588.
[24]	PICAS JOSEP A, RUPÉREZ ELISA, PUNSET MIQUEL, et al. In ﬂuence of HVOF spraying parameters on the corrosion resistance of WC-CoCr coatings in strong acidic environment.Surf. Coat. Technol., 2013, 225: 47-57.
[25]	ZHOU WEI, XIONG JI, WAN WEI-CAI, et al.The effect of NbC on mechanical properties and fracture behavior of WC-10Co cemented carbides.Int. J. Refract. Met. Hard Mater., 2015, 50: 72-78.
[26]	HUANG S G, LIU R L, LI L, et al.NbC as grain growth inhibitor and carbide in WC-Co hardmetals.Int. J. Refract. Met. Hard Mater., 2008, 26(5): 389-395.
[27]	LI NING, QIU YOU-XU, ZHANG WEI, et al.Influence and function of Inhibitor VC/Cr3C2 on the grain growth in super fine WC-Co cermets. Rare Met. Mater. Eng., 2007, 36(10): 1763-1766.