Why does sandblasting prolong molybdenum plate life in vacuum furnace?

The melting point of molybdenum is as high as 2620 °C, and it has strong high temperature resistance, but in practical industrial applications, pure high purity is far from enough. The heating shielding layer, furnace tank support, thermal radiation plate, and other components in the vacuum furnace not only have to withstand the high temperature cycle of thousands of degrees, but also face practical problems such as heat, coating adhesion, and oxide generation.

The essence of the sandblasting treatment is to form a uniform microscopic rough texture on the surface of the molybdenum plate by controlling the abrasive and pressure (Ra values are usually between 3.2-6.3 µ m, which can be based on demand). This seemingly simple roughening process has brought about several key changes:

First of all, it effectively removes the residual oxide layer, oil stains, and tiny impurities in the production process of molybdenum plates, making the surface "clean and toothed". Secondly, the rough texture greatly increases the actual area, providing a strong mechanical anchoring effect for subsequent thermal spraying, ceramic coating, or thermal insulation materials. Many cases in the industry have shown that the coating shedding rate of furnace internal parts using sandblasted molybdenum plates can exceed 50%, and the maintenance cycle is significantly extended.

I have received feedback from some vacuum furnace manufacturers: In the early days, they used bright molybdenum plates as heating shields. The smooth surface is good-looking, but it is easy to slide when installed and fixed, and the adhesion is not enough after coating with high-temperature resistant coatings. Local peeling began to appear, resulting in a decrease in thermal efficiency and an uneven temperature field.

After using sandblasting on the molybdenum plate, these problems have been obviously improved. The rough surface not only improves the coating adhesion but also improves the light reflection at specific wavelengths to a certain extent, helping to achieve better temperature uniformity in some precision heat treatment processes. At the same time, sandblasting can also alleviate the influence of molybdenum recrystallization and embrittlement on the overall structure at high temperature to a certain extent, because a better adhesive layer can share part of the stress.

Of course, the sandblasted surface is not a panacea. In the few occasions where extreme optical performance is required or ultra-low, the bright polished surface still has advantages. However, in the application of most high-temperature structural parts and coating substrates, the comprehensive performance of sandblasting molybdenum plates is more pragmatic.

As semiconductors, new energy materials, and other fields have higher and higher requirements for heat treatment, users no longer "can withstand high temperatures" on molybdenum plates, but pursue lower comprehensive use costs and more stable processes, repeatability. The sandblasting surface treatment just meets this demand-its cost is relatively controllable, the process is mature, and the surface parameters can be controlled repeatedly. It is the conventional choice of many high-end vacuum furnaces and high-temperature equipment manufacturers.

In addition to strictly controlling the purity and thickness tolerances of the substrate, we also pay special attention to the surface uniformity and batch consistency of the sandblasting surface molybdenum plates we supply. Many old customers reported that the most intuitive feeling after using it is "worry-free": it is stable to install, has fewer problems during operation, and is easy to maintain later.

If you are selecting materials for vacuum furnace transformation, semiconductor crystal growth furnace, or high temperature sintering equipment, it is recommended to focus on the solution of sandblasting the surface. Different Ra values correspond to different adhesion requirements, and we can recommend the most matching surface parameters and plate specifications according to your specific working conditions.

The reliability of high-end equipment is often hidden in the humble surface treatment. A properly handled sandblasting molybdenum plate can make the whole set of equipment run for a few more years and stop a few times under harsh conditions. This is not only the choice of materials, but also the guarantee of process stability.

Need us to provide the technical parameter table of a typical sandblasting molybdenum plate, practical application cases, or selection suggestions for your equipment? Communication is always welcome.