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Pengaruh Substrat Terhadap Kekerasan Lapisan NiCoCrAlY Yang Terdeposisi Dengan Teknik HVOF[Effect of Different Substrate on Hardness Properties of NiCoCrAlY Coatings Deposited by HVOF Technique] Desiati, Resetiana Dwi; Sugiarti, Eni; Junianto, Endro; Martides, Erie; Prawara, Budi
Metalurgi Vol 32, No 2 (2017): Metalurgi Vol. 32 No. 2 Agustus 2017
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Micro structure and micro hardness characterizations have been done on NiCoCrAl coating deposited on different substrate, i..e, carbon steel, nickel chrome and hastealloy. NiCoCrAlY coating was deposited by high velocity oxy fuel (HVOF) thermal spraying technique. Characterization and measurents were applied on all cross section of the coating surfaces. Micro structural analysis was characterized by optical microscope with 40x magnification. Moreover, micro hardness tester was utilized to measure the hardness of the sample with 300 gf for 13 second. The hardness data was measured by calculating the average of 3 position of hardness measurement on substrate before coating, after coating and NiCoCrAl coating layer. According to micro structural analysis, it reveald that the thickness of NiCoCrAlYcoating layer was about 370.76 mm, 92 mm, dan 115.73 on carbon steel, nickel chrome and hastealloy substrate, respectively. Surface morfology showed that the coated layer was not flat and porous structure or void on the coated layer. The porosity of the coated layer might effect the mechanical properties of the sample where high procentase of porosity might reduce the hardness of the sample. The hardness of NiCoCrAlY coating was about 349.95, 315.60 and 311.30 HV for carbon steel, nickel chrome and hastealloy substrate, respectively. The distance from interface between coating layer and substrate might effect hardness measurement. More closer to interface could decrease hardness value and it might caused by interdiffusion of coating elements. Thus would be effect to its mechanical properties.AbstrakTelah dilakukan karakterisasi strukturmikro dan kekerasan mikro pada lapisan NiCoCrAlY yang dideposisikan di atas substrat yang berbeda yaitu baja karbon, nikel krom dan hastealloy. Lapisan NiCoCrAlY dideposisikan menggunakan teknik penyemprotan HVOF (high velocity oxy fuel). Proses karakterisasi dan pengukuran dilakukan pada seluruh lapisan dengan irisan melintang. Karakterisasi strukturmikro diamati dengan menggunakan mikroskop optik dengan perbesaran 40x. Selanjutnya untuk pengukuran kekerasan menggunakan kekerasan mikro dengan beban 300 gf selama 13 detik. Data pengujian kekerasan diperoleh dengan mengukur nilai rata-rata dari 3 posisi uji kekerasan pada masing-masing bagian substrat sebelum dilapisi, setelah dilapisi dan lapisan NiCoCrAlY. Berdasarkan hasil karakterisasi strukturmikro diketahui bahwa lapisan NiCoCrAlY berhasil terdeposisi dengan ketebalan 370,76 mm, 92 mm, dan 115,73 mm masing-masing di atas substrat baja karbon, nikel krom dan hastealloy. Morfologi permukaan lapisan menunjukkan bahwa lapisan yang terdeposisi tidak begitu rata dan masih tampak adanya pori atau lubang di area lapisan NiCoCrAlY yang terbentuk. Porositas dari lapisan sangat berpengaruh pada sifat mekanik, semakin tinggi persentase porositas lapisan maka kekerasan akan menurun. Nilai kekerasan lapisan NiCoCrAlY pada substrat baja karbon adalah sebesar 349,95 HV, nikel krom sebesar 315,60 HV dan hastealloy sebesar 311,30 HV. Jarak dengan interface mempengaruhi pengukuran kekerasan. Semakin dekat dengan interface akan semakin menurun nilai kekerasaannya. Hal ini dipengaruhi oleh daerah interdifusi elemen pelapis sehingga mempengaruhi kekuatan mekaniknya.

Analisa Ukuran Partikel Serbuk Komposit NiCrAl dengan Penambahan Reaktif Elemen untuk Aplikasi Lapisan Tahan Panas Desiati, Resetiana Dwi; Sugiarti, Eni; Ramandhany, Safitry
Metalurgi Vol 33, No 1 (2018): Metalurgi Vol. 33 No. 1 April 2018
Publisher : Pusat Penelitian Metalurgi dan Material - LIPI

Dalam makalah ini dibahas mengenai ukuran sampel serbuk NiCrAl yang ditambahkan reaktif elemen yitrium (Y), silikon (Si), hafnium (Hf), dan zirconium (Zr) menjadi paduan NiCrAlY, NiCrAlSi, NiCrAlYSi, NiCrAlHf, NiCrAlZr dengan proses milling menggunakan ball mill selama 36 jam dengan kecepatan milling 25 Hz atau 1500 rpm dan perbandingan antara serbuk dengan ball mill adalah 1:2. Scanning electron microscopy (SEM) digunakan untuk mengkarakterisasi sampel serbuk yang bertujuan untuk mengetahui morfologi sampel seperti bentuk dan ukuran partikel. Gambar digital dari hasil karakterisasi SEM diolah menggunakan software ImageJ untuk mengetahui ukuran partikelnya dan hasilnya pengukurannya dibandingkan dengan data hasil karakterisasi menggunakan Particle Size Analizer (PSA). Berdasarkan hasil analisa dapat diketahui bahwa pengolahan gambar dijital SEM menggunakan ImageJ memiliki keakuratan kurang lebih sebesar 80%. Hal ini disebabkan dari bentuk sampel powder yang tidak homogen dan sebarannya yang tidak merata. Selain itu pula dapat diketahui juga bahwa sampel serbuk paduan NiCrAl, NiCrAlY, NiCrAlSi, NiCrAlYSi, NiCrAlHf, NiCrAlZr setelah pemilingan selama 36 jam mengalami perbesaran ukuran dari kondisi awal atau 0 jam yang disebabkan selama proses pemilingan mengalami aglomerasi dan coldwelding.

SYNTHESIS OF NICRALX MICROPARTICLES USING DRY MILLING AND WET MILLING PROCESSES Ramandhany, Safitry; Triyono, Djoko; Sugiarti, Eni; Desiati, Resetiana Dwi; Sundawa, Risma Yulita
Metalurgi Vol 38, No 2 (2023): Metalurgi Vol. 38 No. 2 2023
Publisher : National Research and Innovation Agency (BRIN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/metalurgi.2023.713

The characteristics of synthesized NiCrAlY and NiCrAlZr composite powders produced by the milling process were investigated to understand the particle size, the shape of particles, and the properties of crystalline structure. The milling process was carried out by combining dry milling with the wet milling method to prevent agglomeration, produce a homogeneous alloy powder, and reduce the particle size. Ethanol was used during the wet milling process as a process control agent. The PSA (particle size analysis) showed that the particle size was effectively reduced from ±70 μm to less than 30 μm. In addition, surface structure analysis characterized by SEM (scanning electron microscope) revealed that particle shape changed from blocky particles after dry milling into flaky, flattened, and fragmented particles after wet milling. An XRD (x-ray diffraction) was used to identify the phases of powders before and after the mechanical milling process. Crystal structure analysis was calculated from the change of peak broadening in XRD peak spectra. The Williamson-hall method has been performed to calculate the strain and crystallite size of synthesized NiCrAlY and NiCrAlZr composite powder in the present study. The findings in this study show the characteristics of powders, which are important information for producing coatings with good performance.

STRUCTURE, MECHANICAL PROPERTIES, AND OXIDATION RESISTANCE OF MN-RICH FE-MN-AL ALLOYS Desiati, Resetiana Dwi; Sutiawan, Edi; Sudiro, Toto; Hermanto, Bambang
Metalurgi Vol 37, No 3 (2022): Metalurgi Vol. 37 No. 3 Desember 2022
Publisher : National Research and Innovation Agency (BRIN)

In this study, Mn-rich Fe-Mn-Al alloys with different Al content (Al = 0, 3, and 5 % by weight) were fabricated from ferromanganese lumps using a conventional powder metallurgy technique. The samples were compacted in 1 cm steel dies using a load of 8 tons and then sintered at 1100 °C for 2 h in a tubular furnace under a vacuum condition of around 0.5 mbar. To evaluate the effect of Al addition to Fe-Mn-Al alloy, the Archimedes principle and Vickers hardness were applied to estimate the density and hardness of the compact alloys. Moreover, the high-temperature oxidation resistance of the alloy was evaluated at 800 °C for 8 cycles. The structure of the alloy before and after oxidation was studied by means of X-Ray Diffractometer and SEM-EDS. The XRD analysis results show that the FeMn-0Al alloy is mainly composed Fe3Mn7 phase, the presence of FeAl phase at 3 wt% Al, and Al8Mn5 phase at 5 wt% Al. The density and hardness of Fe-Mn-Al alloys decreased with the increased Al content. Fe-Mn-Al alloy without Al addition exhibits poor oxidation resistance since the first cycle of the test. The results of microstructural analysis showed that although the alloy with the addition of 3 wt% Al showed less mass gain after being exposed for 8 cycles at 800 °C, the Fe-Mn-Al alloy with 5 wt% tended to be more resistant to oxidation and had no cracking defects. The structure of the oxide formed on the surface of the alloy is composed of two layers (ie; outer and inner layer) which are affected by each alloy composition.

The Effect of Single and Double-Doped Addition on 8YSZ Coating Layers Deposited on Inconel 625 by Electrophoretic Deposition Aini, Kurotun; Amaliyah, Fina Fitratun; Sugiarti, Eni; Desiati, Resetiana Dwi; Latifah, Nurul; Ramandhany, Safitry; Fadilah, Ihah; Nasihah, Aunillah Putri El
Metalurgi Vol 39, No 2 (2024): Metalurgi Vol. 39 No. 2 2024
Publisher : National Research and Innovation Agency (BRIN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/metalurgi.2024.770

The ceramic layers of 8 mol% yttria-stabilized zirconia (8YSZ), singly doped with Fe2O3 and doubly doped with Fe2O3 and Al2O3, have been deposited successfully on Inconel 625 substrates by the EPD (electrophoretic deposition) process. The oxide doping influenced the stability of the EPD suspension and affected the density of the resultant layer. In order to improve the adhesion between the layer and the substrate, a two-step sintering was performed up to 1200 ºC for a total duration of 4 hours in a horizontal vacuum furnace, with a heating rate of 2 ºC per minute in an Argon gas atmosphere. FE-SEM (field emission scanning electron microscopy) and vickers hardness tests were employed to investigate the effect of single and double doping on the morphology and hardness of the coating layers, respectively. EDS (energy dispersive spectroscopy) was employed to analyze the elemental composition of the layers, while XRD (x-ray diffractometry) was utilized to determine the crystalline phases. The results indicated that the double-doped coating sample possesses a better microstructure and the layer with double doping exhibits a denser microstructure and reduced porosity (3.84%) in contrast to the single doping layer (6.05%). The vickers hardness test indicates a rise in hardness from 65.3 HV with single doping to 283.78 HV with double-doping layers, due to the presence of Al2O3 as the interstitial agent, which reduces the layer's porosity and enhances adhesion between the layer and the substrate. Furthermore, the addition of Al2O3 as the double dopant may impede the tà m phase transformation, leading to enhanced thermal stability in the double-doped coating sample compared to the single-doped coating sample. This study shows that double doping techniques can improve the efficiency of ceramic coatings for high-temperature applications, such gas turbine components, and also giving opportunities for more research in oxidation, corrosion, and erosion testing.

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