Q235碳钢化学镀Ni-Fe-P及Ni-W-P研究

发布时间：2018-07-09 22:42

本文选题：化学镀 + Ni-W-P　；参考：《华南理工大学》2015年硕士论文

【摘要】：碳素钢是常用构件如电网线夹和螺栓等的典型用材之一。在沿海地区，由于大气环境的侵蚀性较强，碳素钢制品更易因腐蚀而失效，严重威胁电网安全、经济运行，因此对其进行表面耐蚀强化处理十分必要。化学镀作为一种新兴的性价比高、节能、节材且环保的表面工程技术，能赋予材料优异的防腐、耐磨等综合性能，因此成为材料保护技术重要的研究领域。本文以Q235碳钢基材为研究对象，对其Ni-Fe-P和Ni-W-P化学镀体系进行了系统的研究。论文主要研究内容及结论如下： 1）工艺优化分别以硫酸镍和硫酸亚铁/钨酸钠为Ni-Fe-P/Ni-W-P化学镀主盐，以镀液稳定性、镀速、镀层硬度、镀层P和Fe/W元素含量及其耐蚀性为主要技术指标，基于有效组分筛选结果，以单因素实验分别对主盐、还原剂、络合剂、缓冲剂和稳定剂的添加量以及镀液温度和镀液初始pH值对施镀效果的影响规律进行了研究。经综合分析，锁定镀液稳定、镀速高、镀层综合质量优异的化学镀最佳工艺如下：Ni-Fe-P化学镀：NiSO4·6H2O30g/L， FeSO4·7H2O4.76g/L， HBO36.88g/L，(NH4)2SO424.50g/L，，NaH2PO2·H2O23.59g/L，C6H5Na3O7·2H2O52.36g/L， T901℃，pH9.0；Ni-W-P化学镀：NiSO4·6H2O30g/L，Na2WO4·2H2O40g/L，C6H5Na3O7·2H2O60.83g/L，NaH2PO2·H2O18g/L，C3H6O314.03g/L，(NH4)2SO425.68g/L，H2NCSNH20.02mg/L，T901℃，pH9.0。 2）典型试样微观形貌、成分及硬度分析对最佳化学镀工艺所获镀层分别进行了SEM、EDS和显微硬度分析。表面和截面SEM分析结果表明：镀层与基体结合紧密，无明显界面，镀层厚度分布十分均匀。其中Ni-Fe-P镀层致密，厚度16.10μm；Ni-W-P镀层致密，厚度12.68μm。EDS分析结果表明：Ni-Fe-P镀层化学成分及其含量为8.72%Fe、8.00%P和83.28%Ni；Ni-W-P镀层化学成分及其含量为5.23%W、8.31%P和86.40%Ni。显微硬度测试结果表明：Ni-Fe-P和Ni-W-P镀层镀态硬度分别为534HV和539HV。 3）典型试样腐蚀防护性能综合测试对最佳化学镀工艺所获镀层进行了腐蚀防护性能的综合测试。50℃、3.5%NaCl溶液全浸腐蚀实验结果表明：与碳钢基体比较，Ni-Fe-P和Ni-W-P合金镀层试样的耐蚀性能显著提高，且相同厚度的Ni-W-P镀层的耐蚀能力优于Ni-Fe-P镀层。电化学动电位极化曲线测试结果表明：Ni-W-P和Ni-Fe-P镀层试样的自腐蚀电流密度分别是基体试样的1.11%、2.12%，其开路电位分别比基体的开路电位提高239mV和158mV。
[Abstract]:Carbon steel is one of the typical materials for common components, such as wire clamp and bolt. In coastal areas, because of the strong erosion of atmospheric environment, carbon steel products are more vulnerable to corrosion, which seriously threatens the safety of power grid and economic operation. Therefore, it is necessary to carry out the surface corrosion resistance strengthening mechanism. Electroless plating is a new kind of cost performance. High, energy saving, wood saving and environmentally friendly surface engineering technology can give the material excellent anticorrosion, wear resistance and other comprehensive properties, so it has become an important research field of material protection technology. This paper takes Q235 carbon steel substrate as the research object and studies the system of Ni-Fe-P and Ni-W-P electroless plating system. The main contents and conclusions of this paper are as follows:
1) the main salt was plated by nickel sulfate and ferrous sulfate / sodium tungstate, with the stability of the bath, the speed of the plating, the hardness of the coating, the content of the P and Fe/W elements and the corrosion resistance of the coating as the main technical indexes. Based on the effective component screening results, the main salt, reducing agent, complexing agent, buffer and stabilizer were respectively on the basis of single factor experiment. The effect of the addition amount, the plating solution temperature and the initial pH value of the plating solution on the plating effect was studied. After comprehensive analysis, the best electroless plating process for the plating bath was stable, the plating rate was high and the overall quality of the coating was excellent as follows: Ni-Fe-P electroless plating: NiSO4. 6H2O30g/L, FeSO4. 7H2O4.76g/L, HBO36.88g/L, NH4 2SO424.50g/L, NaH2PO2. H2O23 .59g/L, C6H5Na3O7 / 2H2O52.36g/L, T901 C, pH9.0; Ni-W-P electroless plating: NiSO4. 6H2O30g/L, Na2WO4 2H2O40g/L, C6H5Na3O7 2H2O60.83g/L.
2) the microstructure, composition and hardness of typical samples were analyzed by SEM, EDS and microhardness analysis of the best electroless plating process. The surface and cross section SEM analysis showed that the coating was close to the matrix, without obvious interface, and the thickness distribution of the coating was very uniform. The Ni-Fe-P coating in the coating was compact, the thickness of the coating was 16.10 mu m; the Ni-W-P coating was used. The compact and thickness 12.68 m.EDS analysis results show that the chemical composition and content of the Ni-Fe-P coating are 8.72%Fe, 8.00%P and 83.28%Ni. The chemical composition and content of the Ni-W-P coating are 5.23%W, 8.31%P and 86.40%Ni. microhardness test results show that the hardness of the Ni-Fe-P and Ni-W-P coating is divided into 534HV and impurities in the plating state of the Ni-Fe-P and Ni-W-P coatings.
3) the comprehensive test of corrosion protection performance of typical sample corrosion protection performance of the best electroless plating process is.50 C, and the results of 3.5%NaCl solution full immersion corrosion test show that the corrosion resistance of Ni-Fe-P and Ni-W-P alloy coatings is significantly improved and the corrosion resistance of Ni-W-P coating with the same thickness is compared with that of carbon steel matrix. The test results of electrochemical potential polarization curve show that the self corrosion current density of Ni-W-P and Ni-Fe-P coatings is 1.11%, 2.12%, respectively, and the open potential of the substrate is higher than that of the base body 239mV and 158mV., respectively.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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