沉積TiAlN硬質薄膜提升刀具切削性能之研究

Abstract

氮化物硬質薄膜，高硬度，高化學穩定性，廣用於航太產業、模具加工業、機械業、電子業。可有效提昇刀具，模具的耐磨耗性，降低摩擦係數，有效延長刀具壽命降低生產成本。 本研究目的為濺鍍披覆TiAlN高密度薄膜，提升捨棄式瓷金刀具切削能力。應用反應共濺鍍(co-sputter)，將高密度TiAlN硬質薄膜分別沉積於瓷金刀具及玻璃基材。應用田口實驗設計，L9 (34)直交表，配合變異數分析，反應共濺鍍參數，包括: Ti DC power, Al DC power, N2/(Ar+N2)flow ratio 及Substrate bias。固定基材溫度(200oC)、工作壓力(3×10-3) 、沉積時間(15 min)。沉積TiAlN薄膜的厚度介於316.42 nm~442.59 nm，分析TiAlN薄膜結晶品質(X-Ray)與結晶相，顯微鏡(SEM)觀察表面微結構及氮化物薄膜成份(EDS)。量測薄膜微硬度，楊氐模數及摩擦係數。將鍍層刀具進行鉻鉬合金鋼(SCM415)乾銑削，分析工件表面粗糙度及刀腹磨耗(flank wear)。應用灰關聯分析理論，獲得多重品質特性最佳TiAlN薄膜沉積參數。經實驗驗証顯示，工件表面粗糙度、刀腹磨耗及薄膜硬度改善率分別為26.08%, 26.96%及14.74%。

Transition metal nitride films have been studied extensively because of their high hardness, excellent wear resistance, high oxidation resistance, good thermochemical stability, lower friction coefficient, and the cutter life was extended. In this study, the optimal settings for the deposition parameters of TiAlN thin films that are deposited on cermet cutting tools and glass substrates using direct current (DC) reactive sputtering. The Taguchi method with an L9 (34) orthogonal array, signal-to-noise ratio and analysis of variance were employed to study the performance characteristics. The Taguchi method was used to design a robust experiment. Then deposition parameters of the TiAlN hard films, including Ti DC power, Al DC power, N2/(Ar+N2) flow ratio and Substrate bias were optimized with reference to structure of the films, dry milling tests of SCM415 alloy steel and wear tests of TiAlN films. The effects of the deposition parameters on the structure, morphology and compositional analysis of the TiAlN films were analyzed using scanning electron microscopy (SEM), X-ray diffraction. The TiAlN films with thickness of 316.42 nm~442.59 nm were deposited. Findings the grey-based Taguchi analysis show that the improvement in surface roughness is 26.08%, in flank wear is 26.96%, and in films hardness is 14.74%. The optimum TiAlN coating with the highest hardness, elastic modulus, and H/E values.