A feasible method to ensure normal sealing of molybdenum piece

Normal sealing of molybdenum piece at high temperature is the key to success or failure of molybdenum piece processing. Regarding the technical key points of molybdenum piece sealing, Baoji Jiritong rare metal provides the following matters needing attention.

 

 

 

First of all, at high temperature, molybdenum is easily oxidized in the air, so the temperature of long-life lamp molybdenum - quartz glass seal should not be higher than 3500C without outer bubble shell. Excessive temperature will slowly oxidize the outer part of the seal in contact with the air, resulting in the damage of the seal. Chromium plating on the surface of molybdenum piece can prevent oxidation and raise the working temperature to 5000C. But the research shows that the chemical adhesion between chromium and quartz glass is poor. In order to solve this contradiction, do not put the entire molybdenum piece chromeplated, only in the molybdenum piece and the air contact outside chromeplated. Another disadvantage is that the spot welding performance of molybdenum slice becomes worse after chromium plating.

 

 

 

Secondly, the sealing life of molybdenum pieces was compared.

 

 

 

Based on the above principles, life experiments were carried out on lamps made of various molybdenum pieces without external bubble shells. At the same temperature, such as (1000T/T) =1.5, T≈3800C, the life of MR16 halogen tungsten lamp sealed with yttrium and cerium molybdenum pieces was up to 1200 hours, while that sealed with pure molybdenum pieces was only 650 hours. At high temperatures; For example, T = 5000C, the sealing life of chrome-plated molybdenum piece is 2500 hours, while pure molybdenum piece is only 30 hours.