Modeling of reactively sputtered TiAIN coating on tungsten carbide insert tool its properties and cutting performance in dry turning of AISI D2 steel

• Main Author: Budi, Esmar
• Format: Thesis
• Language: English; English
• Published: 2010
• Subjects: T Technology (General); TA Engineering (General). Civil engineering (General)
• Online Access: http://eprints.utem.edu.my/id/eprint/15716/1/Modeling%20Of%20Reactively%20Sputtered%20TiAIN%20Coating%20On%20Tungsten%20Carbide%20Insert%20Tool%20Its%20Properties%20And%20Cutting%20Performance%20In%20Dry%20Turning%20Of%20AISI%20D2%20Steel.pdf; http://eprints.utem.edu.my/id/eprint/15716/2/Modeling%20of%20reactively%20sputtered%20TiAIN%20coating%20on%20tungsten%20carbide%20insert%20tool%20its%20properties%20and%20cutting%20performance%20in%20dry%20turning%20of%20AISI%20D2%20steel.pdf; http://eprints.utem.edu.my/id/eprint/15716/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=60894

An extended theoretical model of reactive sputtering of TiAIN coating has been developed to study the effect of substrate bias (Vb) and nitrogen (N2) flow rate on the coating composition and deposition rate. The model simulation results showed that the critical N2 flow rate (fn2) to achieve a stoichiometry composition of unbiased (Vb = 0 V) and biased (Vb = -80 V) substrate was 4 seem and 3 seem, respectively. At N2 flow rate lower than fN2, the coating composition increased with an increase in Vb and N2 flow rate due to the increase of ion flux to the substrate while the deposition rate decreased due to the coating densification and the decreased sputtering rate. At N2 flow rate higher than fN2, the coating composition and deposition rate did not depend on the Vb and N2 flow rate due to the domination of neutral particles deposition than ions deposition. The model verification using secondary data showed an accurately prediction on the coating composition and deposition rate at N2 flow rate higher than [N/. The calculated coating composition at N2 flow rate lower than fN2 showed a deviation due to heterogeneous reactions between the sputtered particles (Ti and AJ) and N at the substrate surface, while the deviation of calculated deposition rate was due to coating densification. The experimental investigation was designed by using Response Surface Methodology (RSM) and conducted by using magnetron sputtering in deposition of TiAIN coating on WC inserts. The coating composition and thickness were obtained by using SEM/EDX. The coating structure and morphology were obtained by using XRD and AFM, respectively. The coating hardness and adhesion were obtained by using ultra-micro hardness test and indentation test, respectively. The cutting test was carried out in CNC dry turning of AISI D2 steel. The flank wear and surface roughness were obtained by using optical microscopy and surface roughness tester, respectively. The results showed that generally the coating composition of biased substrate (- I 00, -150, -200 V) was consistently higher than that of unbiased substrate whereas the deposition rate o r biased substrate is lower than that of unbiased substrate. Analysis of the coating thickness showed that generally the coating thickness decreased with an increase , in the Vb and . N2 flow rate. At N2 flow rate lower than 50 sccm, the thinnest coating(- 1000 nm) is achieved by unbiased substrate due to low ions fluxes for reaction at the substrate surface. The coating hardness, structure and morphology were significantly influenced by the V b while' the interaction of the Vb and N2 flow rate significant ly influenced the coating adhesion. The coating hardness increased (-7 GPa)with an increase in the V b up to -200 V due to decreased coating crystal size. At N2 flow rate of 70 seem, the adhesion strength increased with an increase in the Vb up to -200 V due to decreased compressive stress. The lowest flank wear (-0.4 mm) due to high adhesion strength was achieved at -200 \' and 70 seem.