多元复合改性Ag/SnO2触点材料的内氧化法制备与电气性能研究

Preparation and Electrical life performance of the Multi-component Modified Ag/SnO2 Electrical Contact Materials by Internal Oxidation Method

摘要:

为探究掺杂组元类型及含量对多元复合改性Ag/SnO2In2O3触点材料的内氧化法制备工艺、微观结构、显微硬度、温升、电寿命等电气性能的影响规律，采用中频熔炼-铸造工艺制备了改性AgSnIn合金，通过内氧化法制备了多元复合改性Ag/SnO2In2O3触点材料。利用AC-4电寿命型式试验平台对触点材料进行温升、电寿命性能评价。研究表明，改性Ag/SnO2In2O3材料的内氧化工艺优选参数为700 ℃，5 MPa，48 h。相比于Ni、Cu或Zn二元改性而言，Ni-Cu-Zn三元改性AgSn合金内部存在较大的微应变，相应的改性Ag/SnO2In2O3材料的显微硬度随着In元素含量的降低呈先上升后急剧下降。由0.47 wt.%镍，0.4 wt.%铜，0.43 wt.%锌和2.1 wt.%铟元素组成的改性AgSnIn合金可实现完全内氧化，相应的改性Ag/SnO2In2O3材料表现为最佳的显微硬度（1382.49 MPa）、最长服役寿命（28989次）和合适的温升（43.69 K），这归因于显微结构中存在较大的微应变（19×10-3）和起到强化效应的晶界组织。经分析发现，在特定的In含量比例范围2.1~3.1 wt.%，改性Ag/SnO2触点材料的电寿命循环周期与显微硬度大小之间呈正相关性，这一结果将为Ag/SnO2触点材料的配方设计与电寿命性能预测提供新思路。

Abstract:

Silver-based electrical contact materials are the core of low-voltage electrical connection in the fields of new energy power vehicles, industrial electrical appliances and other fields, with the widest range of applications and the largest demand. The Ag/SnO2 contact material system has made great progress due to its excellent electrical contact performance and arc erosion resistance. However, the material system still has problems such as higher temperature rise and shorter electrical life under service. Once it fails, it will lead to major safety accidents such as power system paralysis and out-of-control communication facilities, and economic and social losses are difficult to estimate. Herein, in order to explore the impact of the type and content of the modified components on the preparation process, microstructure, microhardness, temperature rise and electrical life of the modified Ag/SnO2In2O3 contact materials, the modified AgSnIn alloys are synthesized by medium-frequency smelting and casting process, and then the corresponding Ag/SnO2In2O3 contact materials are prepared by internal oxidation method. The AC-4 electrical life type testing platform is used to evaluate the temperature rise and electrical life performance of the materials. The results shows that the optimum parameters of internal oxidation process of the modified Ag/SnO2In2O3 materials are 700℃, 5MPa, 48h. Compared with the binary modification of Ni, Cu or Zn, there exists larger micro-strain in the Ni-Cu-Zn ternary modified AgSnIn alloys, and the microhardness of the corresponding modified Ag/SnO2In2O3 material increases first and then decreases sharply with indium content decreased. The modified AgSnIn alloy, composed of 0.47wt.% nickel, 0.4wt.% copper, 0.43wt.% zinc and 2.1wt.% indium element, could achieve complete internal oxidation. The corresponding modified Ag/SnO2In2O3 material presents the optimum microhardness (1382.49 MPa), the longest cycle number (28989 operations) and the appropriate temperature rise (43.69 K), which is attributed to some larger micro-strain (19×10-3) and grain boundary structure with strengthening effect. By comparison analysis, A positive correlation has been established between the electric life cycle number and the microhardness of the modified Ag/SnO2 material Within In element content ranged from 2.1 to 3.1 wt.%, which will provide a new idea for the formulation design and electric life performance prediction of the Ag/SnO2 contact material.