Enhancing the Hardness of Sintered SS 17-4PH Using Nitriding Process for Bracket Orthodontic Application

Bambang Suharno, Sugeng Supriadi, S. T. Ayuningtyas, T. Widjaya, E. R. Baek

Research output: Contribution to journalConference articlepeer-review

Abstract

Brackets orthodontic create teeth movement by applying force from wire to bracket then transferred to teeth. However, emergence of friction between brackets and wires reduces load for teeth movement towards desired area. In order to overcome these problem, surface treatment like nitriding chosen as a process which could escalate efficiency of transferred force by improving material hardness since hard materials have low friction levels. This work investigated nitriding treatment to form nitride layer which affecting hardness of sintered SS 17-4PH. The nitride layers produced after nitriding process at various temperature i.e. 470°C, 500°C, 530°C with 8hr holding time under 50% NH3 atmosphere. Optical metallography was conducted to compare microstructure of base and surface metal while the increasing of surface hardness then observed using vickers microhardness tester. Hardened surface layer was obtained after gaseous nitriding process because of nitride layer that contains Fe4N, CrN and Fe-αN formed. Hardness layers can achieved value 1051 HV associated with varies thickness from 53 to 119 μm. The presence of a precipitation process occurring in conjunction with nitriding process can lead to a decrease in hardness due to nitrogen content diminishing in solid solution phase. This problem causes weakening of nitrogen expansion in martensite lattice.

Original languageEnglish
Article number012050
JournalIOP Conference Series: Materials Science and Engineering
Volume299
Issue number1
DOIs
Publication statusPublished - 7 Feb 2018
Event1st International Conference on Chemistry and Material Science, IC2MS 2017 - Malang, East Java, Indonesia
Duration: 4 Nov 20175 Nov 2017

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