#TITLE_ALTERNATIVE#

• Main Author: (NIM : 12508020), ABDURRAHMAN
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/20670
• Institution: Institut Teknologi Bandung

Intermetallic compounds of Ti-Al system has the advantages of relatively low density, advanced creep resistance, good oxidation, corrosion, crack propagation resistance, and has a relatively high yield strength at high temperatures. These advantages make Ti-Al intermetallic systems have tremendous potential to be developed in high temperature applications such as turbine parts in aircraft, automotive, and others. Two-phase intermetallic alloys of α2-Ti3Al / γ-TiAl has booth advantages from α2-Ti3Al phase which has a lower brittleness but less resistant to corrosion and γ-TiAl phase which has good corrosion resistance but relatively high brittleness. To increase the oxidation and corrosion resistance two-phase α2-Ti3Al / γ-TiAl intermetallic alloys are normally protected by the formation of coatings on surfaces to prevent susceptibility to oxidation at operating temperatures above 700 º C. In this study, aluminide coatings are used pack aluminizing method. The pack aluminizing process were carried out at a temperature of 850oC for various times of 11 hours, 15 hours, 25 hours, and 40 hours. The composition pack used was 75% Al2O3, 2% NH4Cl, and 23% Al powder (all compositions are in weight percent). At high temperature applications, especially salt-rich environment, the coating degraded caused by hot corrosion. To determine the degradation due to hot corrosion a series of tests was performed at 800 º C for various times of 5, 10, and 20 hours in a mixture of 90%-weight Na2SO4and 10%-weight NaCl environment. The experimental results showed that the thickest coating layer is formed by pack aluminizing process was found for 40 hours with an average thickness results of TiAl3 phase at 85,578 μm. In addition, the hot corrosion test results showed that pack aluminizing for 15 hours has the lowest coating degradation. The depth of corrosion penetration was average 8,173 μm for 20 hours hot corrosion test. Plot between log x (thickness of TiAl3 layer) versus log t (time) pack aluminizing result at 800ºC follows the general equation of: log x = 1.707 log t + 2.5382. XRD test results showed that most corrosion products contain the non-protective oxide TiO2 and Al2O3 in pitting form.