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Abstrak :
Baja Tahan Karat 316L memiliki aplikasi yang sangat beragam, mulai dari platform serta instalasi lainnya, terutama pada lepas pantai karena ketahanan korosinya yang tinggi. Namun, pada penggunaannya, baja tahan karat 316L memiliki kemungkinan untuk terjadi korosi sumuran. Korosi sumuran merupakan korosi yang sulit untuk dideteksi sampai akhirnya terjadi kerusakan. Dengan mengaplikasikan pelapisan aluminium pada baja tahan karat 316L maka korosi sumuran dapat dicegah. Selain itu, ketahanan korosi secara umum juga akan meningkat. Metode untuk mengaplikasikan aluminium pada baja tahan karat 316L adalah dengan electric arc thermal spray aluminum. Pengujian kali ini menginvestigasi ketebalan pelapisan paling baik yang memberikan hasil maksimal, dengan tiga parameter yaitu berkisar antara 90-100 µm, 140-150 µm, and 190 – 200 µm. Ketahanan korosi diuji menggunakan metode polarisasi siklik. Hasil studi menunjukkan bahwa ketahanan korosi dan daya lekat paling baik dihasilkan lapisan dengan ketebalan 190 – 200 µm...... In oil and gas industries, 316L Stainless Steel is widely used to construct platforms and other installations because of its high corrosion resistance. However, 316L Stainless Steel is still susceptible to pitting corrosion which is difficult to be detected before failure starts to happen. By applying aluminium coating on stainless steel, pitting corrosion will be prevented. Moreover, the corrosion rate will decrease and the steel’s lifetime will increase. Using Electric Arc Thermal Spray Aluminium as the method to apply the aluminium, one of the most important factor that influence corrosion rate on aluminium coated stainless steel is the thickness itself. This paper investigates the most effective thickness applied to achieve the best quality of the coating, ranging at 90-100 µm, 140-150 µm, and 190 – 200 µm. The corrosion resistance is tested using the data obtained from the cyclic polarization curve. The study shows that the coating thickness of 190 – 200 µm produces the best corrosion resistance and adhesion strength

Abstrak :
High velocity oxy-fuel (HVOF) sprayed tungsten carbide ? cobalt (WC-Co) coatings exhibit attributes that allow them to be a candidate material for high temperature applications; such as temperature insulators for rocket nozzles. This application note investigates the effect of surface preparation, in this case the grit blasting process, on the characteristics of the so-formed coating. The WC-Co coatings exhibited high hardness and low porosity. The composition of WC-Co coating varied in different regions, but on average was close to the composition of the initial feedstock, implying that there was no preferential loss of the material during the spray process. Microanalysis indicated diffusion of tungsten to the interface between the coating and the substrate and partly explains the high bonding strength of the coating. These physical characteristics suggest that the HVOF sprayed WC-Co is an appropriate coating technology for rocket nozzles.

Abstrak :
Latar Belakang: Penggunaan bahan semen (siler) saluran akar dengan kandungan dan karakteristik berbeda diduga dapat memengaruhi retensi pasak fiber terhadap dinding saluran akar pasca perawatan endodontik. Tujuan : Mengetahui perbedaan kekuatan adhesi pasak fiber pada perawatan saluran akar yang menggunakan siler berbasis resin epoksi dan kalsium silikat. Metode: 30 gigi premolar bawah akar tunggal didekoronasi, dilakukan preparasi saluran akar, lalu dibagi menjadi 3 kelompok; Kelompok 1 (kontrol): gigi tanpa pengisian saluran akar, Kelompok 2: gigi yang menggunakan siler resin epoksi (AH-Plus), dan Kelompok 3: gigi yang menggunakan siler berbasis kalsium silikat (Ceraseal). Setelah pengisian saluran akar, preparasi, dan pemasangan pasak fiber. Selanjutnya gigi dipotong pada area sepertiga tengah akar setebal 2 mm kemudian dilakukan uji push-out bond strength menggunakan Universal Testing Machine. Data dianalisis dengan tes One-way Anova dan post hoc Bonferroni. Hasil: Terdapat perbedaan bermakna nilai push-out bond strength antar kelompok semen resin resin epoksi dan kalsium silikat. Kesimpulan: Gigi yang melalui perawatan saluran akar menggunakan siler resin epoksi memberikan kekuatan adhesi pasak fiber yang lebih baik dibandingkan gigi yang menggunakan siler kalsium silikat. ......Background: The use of root canal sealers with different composition and characteristics is thought to effect the retention of fiber post in root canal walls after endodontic treatment. Objective: To evaluate the difference of the fiber post adhesion strength after endodontic treatment using epoxy resin and calcium silicate based root canal sealer. Methods: 30 samples of single-rooted lower premolar were decoronated, got the root canal prepared, then divided into 3 groups; Group 1 (the controls): samples without root canal filling, Group 2 and 3, the canals were filled with gutta percha using epoxy resin (AH-Plus), and calcium silicate (Ceraseal)-based root canal sealer. After root canal obturation, the gutta percha were partly removed, prepared for post space, and then cemented with the fiber posts. Then 2 mm thick disk were cut from the middle root section and subjected to a push-out bond strength test. Data were analysed using the one-way ANOVA and post hoc Bonferroni test. Result: There was a significant difference in the push-out bond strength value between the epoxy resin and calcium silicate-based root canal sealer groups. Conclusion: The endodontic treated tooth previously using epoxy resin root canal sealer gave better fiber post adhesion strength compared to tooth that used calcium silicate based root canal sealer.

Abstrak :
Baja ASTM A36 merupakan mild carbon steel yang banyak digunakan pada sektor infrastruktur, namun demikian baja karbon memiliki ketahanan korosi yang lebih rendah dibandingkan dengan jenis baja lainnya, yang menyebabkan material ini rentan terhadap korosi dalam lingkungan atmosferik. Oleh sebab itu, untuk meningkatkan ketahanan korosinya, baja ASTM A36 dapat dilapisi dengan glass flake epoxy. Penelitian ini bertujuan untuk mempelajari pengaruh perbedaan metode surface cleaning terhadap kekuatan adhesi glass flake epoxy yang diaplikasikan pada substrat baja tersebut dan ketahanan korosi yang dihasilkannya. Dalam penelitian ini diterapkan 5 (lima) jenis metode surface cleaning yaitu: (i) solvent cleaning, (ii) hand tool cleaning, (iii) power tool cleaning, (iv) power tool to bare metal cleaning, serta (v) abrasive blast cleaning. Selanjutnya, dilakukan proses pengukuran kekasaran permukaan dari masing-masing sampel baja ASTM A36 menggunakan metode field test, sebelum diaplikasikan cat dilakukan pengecekan kondisi lingkungan terlebih dahulu (dry and wet temperature, steel temperature, dew point temperature, serta relative humidity), kemudian glass-flake epoxy diaplikasikan pada permukaan substrat baja menggunakan roller paint brush. Setelah itu, dilakukan pengukuran wet dan dry film thickness. Metode analisis data dilakukan per lima sampel dari masing-masing pengujian yang dilakukan yakni pengujian salt spray, pengujian electrochemical impedance spectroscopy, serta dua pengujian adhesi yaitu pull off adhesion dan tape test test. Hasil penelitian menunjukkan bahwa kemampuan organic coating dipengaruhi oleh perbedaan metode surface cleaning yang diterapkan. Abrasive blast cleaning memiliki ketahanan korosi yang paling baik dengan rata-rata pelebaran (creepage) korosi paling rendah yakni 0.49 mm yang termasuk ke dalam rating number 9, dan kekuatan adhesi rata-rata tertinggi yaitu 3.16 MPa. Dengan demikian dapat disimpulkan bahwa, ketahanan korosi dipengaruhi oleh tingkat kebersihan, sementara kekuatan adhesi dipengaruhi oleh tingkat kekasaran. ...... ASTM A36 steel is a mild carbon steel that is widely used in the infrastructure sector; however, carbon steel has a lower corrosion resistance compared to other types of steel, which makes this material susceptible to corrosion in atmospheric environments. Therefore, to improve its corrosion resistance, ASTM A36 steel can be coated with glass flake epoxy. This research aims to study the effect of different surface cleaning methods on the adhesion strength of glass flake epoxy applied to the steel substrate and the resulting corrosion resistance. In this research, five types of surface cleaning methods were applied, namely: (i) solvent cleaning; (ii) hand tool cleaning; (iii) power tool cleaning; (iv) power tool to bare metal cleaning; and (v) abrasive blast cleaning. Subsequently, the surface roughness measurement process for each ASTM A36 steel sample was carried out using the field test method. Prior to applying the paint, environmental conditions were checked first (dry and wet temperature, steel temperature, dew point temperature, and relative humidity), and then glass-flake epoxy was applied to the surface of the steel substrate using a roller paint brush. Afterward, wet and dry film thickness measurements were taken. The data analysis method was carried out on five samples from each test carried out, namely salt spray testing, electrochemical impedance spectroscopy testing, and two adhesion tests, namely pull-off adhesion and tape test tests. The results show that the organic coating ability is influenced by the different surface cleaning methods applied. Abrasive blast cleaning has the finest corrosion resistance with the lowest average corrosion creepage of 0.49 mm, which is included in rating number 9. In addition, the resulting average adhesion strength is also high at 3.16 MPa. It can be concluded that corrosion resistance is influenced by the degree of cleanliness, while adhesion strength is influenced by the degree of roughness.