Nano-Indentation Characteristics of Surface Layer with Fine Conical Protrusions Formed by Sputter Etching of W-Cr Tool Steel

Abstract

The sputter etching was carried out on a W Cr tool steel specimen quenched at 1373 K using argon plasma to form conical or ring shaped carbide protrusions on the surface. Nano indentation tests were used to investigate deformation characteristics of the protrusions from load P vs. displacement h curves at maximum loads of 10, 50 and 245 mN. For the surface layer with conical protrusions, the P h curve at the maximum load of 245 mN is almost similar to that of the specimen without sputter etching. The reason is explained by a balance of two factors, i.e. the hard carbide layer decreases the deformation during the indentation, while the soft region formed by the depletion of carbide forming elements under the carbide layer increases the deformation especially after the carbide layer is cracked by the indentation. When the maximum indentation load is 10 mN, the scatter of P h curves appears reflecting different indentation positions such as the top or side of the protrusions. For a mixture of the thick block like layers with ring shaped protrusions and the matrix areas surrounded by them, the maximum displacement and recovery after unloading are both large when the maximum load is 245 mN. The reason will be that the elastic deformation of the thick block like layers supports the indentation load decreasing the plastic deformation of the soft region under the layers. When the indentation load is 10 mN, the scatter of displacement is very large depending on the indentation either to the protrusions or to the soft matrix region. Tempering after the sputter etching increases the deformation resistance of the whole layer perhaps due to the precipitation of fine carbides in the soft region under the carbide layer.

Enhancement of Visible Light Absorbance and Hydrophobicity by Sputter-Coating of PTFE onto Fine Protrusions Formed by Sputter-Etching of Steels

“…The protrusions formed by sputter-etching will be widely applicable to various engineering purposes due to their multi-functions as well as their simple and economical fabrication process using only argon gas and commercially supplied metals. The protrusions proved to have excellent mechanical properties 33,35,36) with only small decrease in pitting corrosion resistance. 32) They can be used as dies to form fine holes on a polymer film to reduce the light reflection or to facilitate the adhesion of printing ink and a transportation roll for papers and cloths, etc.…”

Large Scale and Orientation-Controllable Nanotip Structures on CuInS2, Cu(In,Ga)S2, CuInSe2, and Cu(In,Ga)Se2 by Low Energy Ion Beam Bombardment Process: Growth and Characterization

“…These advantages meet the demands for industrial processes. Some previous studies have reported that a nanostructured surface could be formed on unary (Si, − Ge, , Co, Ag, Ti, Cu, Sn, Ta, and C), binary (InP, InSb, InAs, GaAs, GaSb, WO 3 , CdS, CaF 2 , , KBr, CdTe, SiO 2 , and NiO), minerals (mica), tool steel, and polymer (PTFE and PMMA) by controlling ion sputtering parameters precisely.…”

Formation of Fine Holes and Protrusions on Ti-6Al-4V Alloy by Argon-Ion Sputter-Etching

“…． 著者らも，これまでに，低合金鋼 7) ，ステンレス鋼 [7][8][9][10][11][12][13][14] ，工 具鋼 7,10,15) ，銅合金 16,17) などのスパッタエッチングを行い，直 径が 200 nm-50 µm の円錐状，円柱状あるいはリッジ状の突 起物が高密度で形成されることを明らかにし，突起物のもつ 光吸収特性 9,11,12) ，電子放出特性 17) ，超撥水・超親水性 10,12) ， アンカー効果 8) ，グリップ・穴あけ特性 13,14) などの機能につ いて調べた． ところで，チタンおよびチタン合金は，他の金属に比べて 軽量で比強度が大きく，耐食性に優れている．また，チタン およびある種のチタン合金は生体に対して無毒であり，すで にチタン合金製インプラント表面に微細構造を形成させて生 体適合性を高める試みが行われている [18][19][20][21] ．著者らは，前 報 22) において，工業用純チタンを SUS304 ステンレス鋼円板 上に載せてアルゴンイオンでスパッタエッチングすると，底 面直径が数 µm の円錐状突起物が形成されることを示した． また，工業用純チタンを V または Ta 円板上に載せてスパッ タエッチングすると直径が 500 nm 以下の微細孔が形成され るが 23,24) ，Nb，Mo および W 円板上に載せてスパッタエッチ つぎに，Fig. Ti-6Al-4V 合金のアルゴンイオンスパッタエッチングによる微細孔および微細突起物の形成…”