本文選題：碳化物陶瓷-金屬復(fù)合粉體 + 化學(xué)活化預(yù)處理　； 參考：《浙江理工大學(xué)》2015年碩士論文

【摘要】：激光熔覆技術(shù)的基礎(chǔ)是制備性能優(yōu)良的喂料粉體�；瘜W(xué)鍍是制備金屬包覆型復(fù)合粉體的先進(jìn)方法，其制備的復(fù)合粉體有效潤濕了陶瓷粉體，實現(xiàn)了粉體顆粒均勻分散，且粒徑大小和金屬包覆量均可控，有效解決了傳統(tǒng)復(fù)合粉體制備過程中的團(tuán)聚和混合不均勻問題，為性能優(yōu)良的涂層制備奠定了基礎(chǔ)。本文采用化學(xué)活化對碳化物陶瓷粉體進(jìn)行預(yù)處理，不同于傳統(tǒng)陶瓷粉體催化活化機理，以新生的表面缺陷作為活性中心，然后利用低溫超聲化學(xué)鍍的方法將金屬直接沉積在其表面，縮短了陶瓷-金屬復(fù)合粉體生產(chǎn)工序、降低了生產(chǎn)成本、提高了復(fù)合粉體質(zhì)量。 采用化學(xué)活化低溫超聲化學(xué)鍍工藝，在WC和SiC陶瓷粉體表面均勻包覆了金屬Ni、Ag層，制備了不同粒徑大小的WC-Ni、WC-Ag、SiC-Ni等碳化物陶瓷-金屬復(fù)合粉體。碳化物陶瓷粉體本身均具有一定的表面催化活性，WC陶瓷粉體由于表面獨特的電子結(jié)構(gòu)，本身催化活性較強，不經(jīng)過化學(xué)活化預(yù)處理也能夠啟動化學(xué)鍍。碳化物陶瓷粉體經(jīng)化學(xué)活化后，新生的表面缺陷與粉體表層特殊的電子結(jié)構(gòu)復(fù)合增強其表面催化活性，不僅提高了鍍層均勻性，而且增強了兩相間的結(jié)合。以新生缺陷為形核中心，，還原金屬Ni (Ag)沿三維生長方式均勻鋪滿碳化物陶瓷粉體表面，最終形成包覆完整的陶瓷-金屬芯核結(jié)構(gòu)復(fù)合粉體。 采用化學(xué)活化低溫超聲化學(xué)鍍制備的WC-Ni復(fù)合微粉為喂料粉體，利用CO2激光熔覆在45鋼基體表面制備性能優(yōu)良的耐磨損涂層，獲得了WC顆粒均勻分布的枝晶狀熔覆層組織，涂層與基體之間屬冶金結(jié)合，結(jié)合非常牢固。涂層試樣的硬度顯著提高，最高硬度接近1200HV。涂層的比磨損率比基體試樣的下降了95.8%，45鋼基體經(jīng)激光熔覆WC-Ni復(fù)合涂層后，抗塑性變形以及粘著磨損的能力得到提高，其磨損特征主要表現(xiàn)為磨粒磨損。
[Abstract]:Laser cladding technology is based on the preparation of fine feed powder. Electroless plating is an advanced method for the preparation of metal coated composite powders. The composite powders are effectively wetted and dispersed uniformly, and the particle size and the amount of metal coating can be controlled. The problem of agglomeration and mixing inhomogeneity in the preparation of traditional composite powders is effectively solved, which lays a foundation for the preparation of coatings with excellent properties. In this paper, the pretreatment of carbide ceramic powder by chemical activation is different from the catalytic activation mechanism of traditional ceramic powder, and the new surface defects are used as the active center. Then the metal was deposited directly on its surface by low temperature ultrasonic electroless plating, which shortened the production process of ceramic and metal composite powder, reduced the production cost and improved the quality of composite powder. The surface of WC and SiC ceramic powders was uniformly coated with NiAg-Ag layer by chemically activated low-temperature ultrasonic electroless plating. Carbide ceramics and metal composite powders were prepared with different particle sizes of WC-NiOWC-AgSiC-Ni. The carbide ceramic powders have a certain surface catalytic activity. Because of the unique electronic structure of the surface, the carbide ceramic powders have strong catalytic activity and can start electroless plating without chemical activation pretreatment. After being chemically activated, the surface catalytic activity of the carbide ceramic powder was enhanced by the composite of the new surface defects and the special electronic structure of the powder surface, which not only improved the uniformity of the coating, but also enhanced the bonding between the two phases. Taking the new defect as the nucleation center, the reduction metal Ni + Ag was uniformly covered with carbide ceramic powder surface along the three dimensional growth mode, and finally the composite powder coated with the ceramic core structure was formed. The WC-Ni composite powder prepared by chemical activation low temperature ultrasonic electroless plating was used as the feed powder. The dendrite cladding structure with uniform distribution of WC particles was obtained by CO2 laser cladding on the surface of 45 steel. It is a metallurgical bond between the coating and the substrate, and the bonding is very firm. The hardness of the coating sample was improved remarkably, and the highest hardness was close to 1200 HV. The specific wear rate of the coating is lower than that of the substrate sample. After laser cladding the WC-Ni composite coating, the resistance to plastic deformation and adhesion wear is improved. The wear characteristics of the coating are mainly abrasive wear.
【學(xué)位授予單位】：浙江理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ174.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 時刻,黃英,李鵬,廖梓s

本文編號：1958856