Sintering microstructure and properties of copper powder prepared by electrolyzation and atomization

The almost completely dense copper was prepared by ultrafine copper powder prepared with both methods of electrolysis and novel water-gas atomization through cold isostatic pressing(CIP)and sintering under atmospheric hydrogen.Fine copper powder possesses the higher sintering driving force,thereby promoting shrinkage and densification during the sintering process.The grain size of sintered samples by electrolytic copper powder is smaller than that prepared by the atomized copper powder,and the twin crystals are particularly prone to forming in the former sintered microstructure due to the raw powder with low oxygen content and high residual stress originating from the CIP process.The relative density of samples by electrolytic and atomized powder at 1000℃ sintering temperature achieves 99.3%and 97.4%,respectively,significantly higher than that of the powder metallurgy copper parts reported in the literature.Correspondingly,the ultimate tensile strength and yield strength of samples by both kinds of copper powder are approximately similar,while the elongation of the sintered sample by the electrolytic powder(60%)is apparently higher than the atomized powder(44%).The superior performance of samples fabricated by electrolytic powder is inferred from the full density and low oxygen level for there is no cuprous oxide in the grain boundaries.

粉末冶金铜铁合金的组织与性能

分别以元素混合粉、机械合金化粉和水气联合雾化合金粉为原料,结合冷等静压成形、烧结及轧制工艺制备了Cu‒5%Fe合金(质量分数),对比了三种原料粉的铜铁合金粉末形貌、微观组织、力学性能及物理性能。结果表明,铁颗粒分布均匀,元素混合、机械合金化和水气联合雾化法粉末烧结体中铁颗粒平均尺寸分别为9.4μm、1.2μm、3.5μm。水气联合雾化法合金样品综合性能最优,抗拉强度550 MPa,导电率59.5%IACS,磁饱和强度9.1 emu·g^(-1)。

信托产品净值化的相关问题探析

自2018年4月资管新规发布以来,信托产品的净值化管理成为了整个信托行业统一面临的难题。信托产品中部分标准化项目已经符合净值化的管理要求,但是对于大部分的非标类业务来说净值化管理究竟如何做?核算的净值是否真实准确的反映了产品的价值?行业是否会有统一的规范指引?这些问题都是每一个管理人需要面临和思考的问题。今年7月31日,资管新规的过渡期又延长了一年,这对于整个资管行业来说,又有了一年的喘息的机会,但是净值化管理依然是无法忽略的一个重大事项,下面笔者将就现有业务的情况,简要阐述一下非标产品净值化的做法以及思考。

资管产品适用金融工具新准则的探讨

根据财政部于2017年最新修订的金融工具会计准则的要求,新准则最晚将于2021年1月1日起全部执行,资管产品也将面临着新旧准则的转换问题。由于资管产品涉及的金融工具较多,且结构涉及复杂,面临准则转换的难度更大,需要更多的专业判断。由于资管行业的风险频繁暴露,资管产品面临的金融工具的减值确认也将更加复杂,金融工具的减值确认成为此次准则转换需要面临的主要难点,也是资管产品净值化需要面临的痛点。