Effect of Metallic Zn Powder on Oxidation Resistance of Al_2O_3-C Refractories

Al2O3-C specimens were prepared by using tabular corundum, flaky graphite, Al, Si, and Zn powder as starting materials and phenolic formaldehyde resin as binder. Keeping the mass ratios of tabular corundum, flaky graphite, Al and Si constant, different contents of Zn （0,0. 5%, 1%, 2% and 3% ） were added respectively. The specimens were/teat treated at 120 -220℃ for 24h, and then fired at 1400℃ for 3h in air atmosphere. The mass change rate, thickness of decarburization layer, apparent porosity, bulk density and microstructure of the products were determined and observed by means of SEM and EDX. The results show that the specimen with 2% Zn was characterized by minimum in thickness of decarburization layer and in apparent porosity and maximum in bulk density. Consequently, the specimen with 2% metal Zn is supposed to perform the best oxidation resistance.

掺杂氧化钇和富镧钐渣对连铸水口MgO-C耐火材料性能的影响

本研究分别考察了氧化钇(Y_(2)O_(3) )和富镧钐渣掺杂量对MgO-C耐火材料微观结构、烧结性能、力学性能和抗稀土钢侵蚀性能的影响。结果表明,Y_(2)O_(3) 和富镧钐渣通过与SiO_(2)和Al_(2)O_(3)反应而生成稀土硅酸盐和稀土铝酸盐,促进材料烧结,提高材料致密性。随着Y_(2)O_(3) 和富镧钐渣掺杂量增大,MgO-C耐火材料的体积密度、抗折强度和耐压强度均先增大后减小,而显气孔率的变化趋势相反。当Y_(2)O_(3) 和富镧钐渣的掺杂量分别为0.5%时,MgO-C耐火材料的体积密度分别为2.87 g/cm^(3)和2.85 g/cm^(3),显气孔率分别为9.6%和10.2%,抗折强度分别为7.6 MPa和6.8 MPa,抗压强度分别为46.4 MPa和41.2 MPa,致密性和常温力学性能提高的幅度最大,抗Ce基稀土钢侵蚀性能相比未掺杂稀土氧化物的试样分别提高了7.6%和10.2%。

含钛熔渣对镁炭质耐火材料的侵蚀

采用静态浸渍法和动态浸渍法研究了TiO2 含量在 2 .4%～ 30 %之间的含钛熔渣对镁炭质耐火材料的侵蚀 ,对侵蚀后试样进行了SEM、XRD和能谱分析 ,提出了含钛熔渣对镁炭质耐火材料的侵蚀机理 :熔渣与耐火材料接触并发生作用 ,熔渣中的TiO2 、FeO等氧化物使耐火材料氧化脱碳并且形成低熔物 ;脱碳及低熔物的熔出使耐火材料孔隙和通道增多 ,这反过来又使熔渣渗入耐火材料内部的速度加快 。

难熔高熵合金研究进展

高熵合金是近年来的新兴领域,与传统合金不同,其一般是由五种或者五种以上主要元素组成,每种主元的含量在5%~35%(原子分数)之间,多种元素混乱排列却拥有简单的相结构,高熵合金的优点显著,发展空间巨大。以难熔金属元素为基础的难熔高熵合金近年来大受关注,含有3种及以上的难熔金属组成的高熵合金称为难熔高熵合金,由于难熔金属的熔点均较高,因此难熔高熵合金表现出了较好的高温力学性能和高温抗氧化性能以及耐腐蚀性能,受到大众欢迎,有望取代传统的高温合金。详细的阐述了难熔高熵合金的制备方法、相结构、力学性能、抗氧化性能与耐腐蚀性能,最后对难熔高熵合金的发展进行了展望。