Font Size: a A A

Study On Preparation Of Mo/Pt/Ag Laminar Metal Matrix Composites Based On Anodization

Posted on:2018-10-13Degree:MasterType:Thesis
Country:ChinaCandidate:P F ZhangFull Text:PDF
GTID:2381330596467025Subject:Materials engineering
Abstract/Summary:PDF Full Text Request
The spacecraft's energy is mainly provided by solar cells,and its service time is controlled by the life of the solar arry which depends mainly on the life of the inter-links.Ag are used as the space solar array interconnect materials.However,Ag interconnects are prone to cracking and being peeled off due to the presence of atomic oxygen and thermal cycling in low Earth orbit,resulting in a reduction in the service life of the solar cell.Mo/Pt/Ag laminar metal matrix composites?LMMCs?can instead of Ag used as inter-links to improve the service of solar cell.However,due to the relatively low surface activity of Mo,the actual binding of Mo-Pt is still very difficult despite the fact that Mo-Pt can dissolve into each other,resulting in a low bonding strength at the Mo/Pt interface.In order to improve the bonding strength of Mo/Pt interface,this paper presents the preparation of Mo/Pt/Ag LMMCs by anodizing Mo foil firstly to improve the surface activity of Mo foil,then electroplating platinum and silver.The main contents and results of this paper are as follows:Firstly,we discussed and compared the anodic oxidation of Mo foil under NaF,HF and NH4F electrolyte system.It was confirmed that the aodic oxidation under NH4F electrolyte system can prepare nano-porous structure of Mo surface.The best anodizing process parameters as follows:1.3wt%NH4F,10vol%H2O and 90vol%ethylene glycol;the anodizing voltage is 20 V and anodizing time is 15 minutes.The test results show that the surface activity of Mo foil with surface nano-porous structure after anodic oxidation is effectively improved.Secondly,we studied the deoxidation process of nano-porous active layer on the surface of anodized Mo foil.And,it is confirmed that the hydrogen reduction annealing process is effective to reduce the oxygen content on the surface of anodized Mo foil.It is found that as the hydrogen reduction annealing temperature increase,the surface nano-porous structure gradually melts and collapses through comparing of Mo foil surface morphology and oxygen content after hydrogen reduction annealing at different temperatures.It was confirmed that the Mo foil annealing at 650?C for 3hours can kept ordered anodized nanoporous morphology and a lower oxygen content.The test results show that the deoxidation process has little effect on the activity of the nano-porous Mo foil.Finally,the Mo/Pt/Ag LMMCs were prepared on the basis of anodized Mo foil with nano-porous structure.Then,we analyzed the surface morphology and composition,tensile strength test,fracture morphology of Mo/Pt/Ag LMMCs.It is found that the bonding strength of Mo/Pt/Ag LMMCs prepared under the two pretreatment conditions is significantly improved,which can meet the requirements of GJB2602-1996 and 160 gf proposed by space users.This indicates that the increase of the interfacial bonding strength between Mo/Pt is due to the increase of the activity of the Mo nano-porous structure.
Keywords/Search Tags:Anodization, Surface activity, Nano-porous structure, Mo/Pt/Ag LMMCs
PDF Full Text Request
Related items