<p>The adoption of 0.2% BeCu alloy and its related products inherit the technology of the late Dr. Fumio Watanabe of Vaclab Co., Ltd. who was involved in the development for many years. This was due to a strong desire to achieve E-13Pa. In order to achieve this, He started with the development of key points, the Q material, the S vacuum pump, and the P vacuum gauge (Fig. 1). Vacuum structure material to replace stainless steel, 0.2%BeCu alloy has been used as a vacuum structure material for XHV/UHV due to its high thermal conductivity and low thermal emissivity, and has been used for many years as a low outgassing technology. As a result, it is now used in vacuum gauges and mass spectrometers, and has successfully commercialized many products such as vacuum Nipple connections, vacuum chambers, and NEG pumps. However, due to the material's high thermal conductivity, electron beam or laser welding is difficult, so forged blocks are manufactured by mechanical cutting now. In addition, processing technology with 5-axis control may be required, but it will be extremely expensive. At this time, we will introduce the results of using the latest Hybrid Lasers and its welding technology, with the aim of improving manufacturing processes, reducing costs, and responding to various shape requirements. Here we will describe the characteristics of the 0.2% BeCu alloy and its manufacturing process. When this alloy is heat treated at 400℃ for 3 days using a vacuum furnace, almost 100% of the alloy surface is covered with Be atoms in the bulk. (Fig.2). During this process, the hydrogen dissolved in the bulk is sufficiently degassed. After cooling and purging with oxygen, the Be metal forms a stable oxide film of BeO, which absorbs water. This oxide film becomes a barrier film that prevents re-dissolution of the hydrogen generated by the hydrogen gas release rate of the 0.2% BeCu alloy treated with BeO is as low as 5E-13 Pa m/s, which is 1/100 of Stainless Steel and 1/10 Titanium alloy subjected to similar treatment. However, because the BeO film is thin, the part facing the atmosphere is oxidized during baking, and the CF edge of the flange cold-bonds with the copper gasket and adheres to it. Electroless nickel plating (NiP) was applied to the 0.2% BeCu product. NiP plating can form uniform plating on any complex shape, and increases surface hardness. CF flanges with this NiP plating reliability of the gasket is extremely high, and even after repeated baking at 250°C, no peeling of the plating or knife edge defects will occur. In addition, the coefficient of thermal expansion of the 0.2% BeCu alloy perfectly matches that of the pure copper gasket, so it is possible to connect a stainless-steel CF flange and a copper gasket (Fig.3). The manufacturing process consists of a forged block, mechanical cutting, NiP plating, removal of the NiP plating on the vacuum side (contact surface), chemical polishing of the copper surface, and BeO film formation in a vacuum furnace. The problem with laser welding of Cu that heat diffusion is fast and light absorption is low in the IR region, so stable heat input is not possible, resulting in unstable welding and vacuum leaks. As a method to solve this problem, Furukawa Electric Industry's Hybrid Laser has good results were obtained using BRACE®-X (Blue 1kw, IR 3kw), which combines Blue + IR lasers, so we will explain it at Oral Session. (Fig.4)</p><p>References</p><p>1) Fumio Watanabe: J. Vac. Sci. Technol. A22 (2004) 181 & 739. 2) Fumio Watanabe: J. Vac. Soc. Jpn, Vol. 56, No. 6, 2013 3) https://www.furukawa.co.jp/fiber-laser/product/lineup/hybrid_blue.html</p>