PENGARUH KADAR SALINITAS AIR TERHADAP LAJU KOROSI BAJA ST 60

Daerah perairan dapat menimbulkan risiko serangan korosi yang lebih tinggi terutama pada lingkungan perairan yang mengandung salinitas atau salinitas, umumnya korosi yang terjadi di perairan dapat menyerang logam, salah satunya adalah baja ST 60 yang banyak digunakan sebagai bahan konstruksi dalam konstruksi bangunan. pelabuhan, jembatan, poros baling-baling, dan aplikasi lain yang terkait dengan lingkungan perairan. Dampak yang ditimbulkan adalah logam dapat mengalami serangan korosi dengan cepat akibat berinteraksi dengan lingkungan air yang mengandung salinitas sehingga logam tersebut akan mengalami kerusakan dan kehilangan sifat teknisnya. Pada penelitian pengujian perendaman dilakukan dengan 3 minggu terus menerus dan 3 minggu (dengan 2 minggu perendaman kemudian 1 minggu tidak terendam) menggunakan air laut yang berasal dari pantai takisung, pelaihari dengan salinitas 2,48% dan air payau yang berasal dari dataran tinggi banjarmasin dengan salinitas 1,25%. Hasil penelitian menunjukkan laju korosi tertinggi terjadi pada 3 minggu perendaman terus menerus dengan air laut yang memiliki salinitas 2,48% dan jenis korosi yang terbentuk adalah korosi seragam. Water areas can pose a higher risk of corrosion attack, especially in aquatic environments that contain salinity or salinity, generally corrosion that occurs in the waters can attack metals, one of which is ST 60 steel which is widely used as construction material in the construction of ports, bridges, propeller axis, and other applications related to the aquatic environment. The impact caused is that the metal can experience corrosion attacks quickly due to interacting with the water environment containing salinity so that the metal will experience damage and lose its technical properties. In the study immersion testing was carried out with 3 weeks continuously and 3 weeks (with 2 weeks immersion then 1 week not submerged) using seawater originating from takisung beach, pelaihari with salinity of 2.48% and brackish water originating from the high land area of banjarmasin with a salinity of 1.25%. The results showed the highest corrosion rate occurred at 3 weeks of continuous immersion with seawater which had a salinity of 2.48% and the type of corrosion formed was uniform corrosion.

Rotary Fatigue Testing Device for Determining Drilling Fluid Compatibility in A Pdm Stator

The purpose of this study was to evolve the understanding between mud motor power section reliability and oil-based drilling fluid chemistry, using novel laboratory data recorded from a proprietary test apparatus and instrumentation. The underlying objective is driven by operator's desire to maximize drilling performance by extending the operating envelope of the PDM/drilling fluid system, beyond what is possible using legacy ASTM immersion testing. This paper describes a new test method and machine, intended to complement currently existing test methodologies, that incorporates multiple interplaying downhole conditions. Twelve fluids were analyzed using the novel test machine and the results compared to data obtained from conventional ASTM immersion testing; The fluids varied with respect to base oil type, as well as concentrations of emulsifier, and wetting agent. The goal of testing was to determine if positive displacement motor (PDMs) elastomer failure mechanisms (abrasion, cracking, chunking) could be replicated in a controlled environment, and if doing so could improve the data and understanding of its lifespan in a PDM. The result of testing provided evidence of two and three body abrasion, compression set, chunking, and chemical swell. It was found that concentrations of additives, as well as base oil type significantly affect runtime in the novel test machine, even if the differences in conventional testing were inconclusive. The novel test machine demonstrated that concentrations of key additives, as well as base oil type significantly affect elastomer runtime, even if conventional testing showed inconclusive results.

Effect of hydroxyapatite/alumina composite coatings using HVOF on immersion behavior of NiTi alloys

Hydroxyapatite (HA) coatings have been widely used to improve biocompatibility of metal alloys. This paper discusses the effect of hydroxyapatite (HA) and HA/alumina coated NiTi on their corrosion and dissolution behavior in Phosphate Buffer Saline (PBS) and Ringer’s lactate solutions. The HA was synthesized from biogenic method and used as initial powder in High-Velocity Oxygen Fuel (HVOF) spray technique for the deposition of two coating types, fully HA and HA + 15 wt.% alumina composite coating. The as-synthesized HA had irregular porous structure with relatively low Ca/P ratio of 1.52. Tafel polarization curves obtained from electrochemical test had showed that both coatings increased the corrosion resistance of the NiTi substrates significantly. The ICP-MS analysis results that indicated a low nickel dissolved in both solutions after immersion in 21 days had supported these findings. The nickel levels in the solutions from all samples, either bared substrate or coated samples, in fact below the maximum limit for allergies of the human body. Immersion testing showed the stability of HA and HA/alumina layers as a barrier which maintains its morphology in PBS solution but slightly changed in Ringers.

Pemanfaatan Batu Gunung Tambolang Kabupaten Toraja Utara Pada Campuran Laston AC-BC

This research was conducted to determine the aggregate characteristic value, the AC-BC mixture design, and the Marshall stability value of the remaining AC-BC mixture design through the Conventional Marshall and Marshall Immersion testing with reference to the 2018 General specifications (Division 6) of the Ministry of PubIic Works and PubIic Housing of the RepubIic of lndonesia. and SNI Testing Standards. Before designing the composition for Conventional Marshall testing and making test specimens to obtain residual Marshall stability, the first thing to do is test the characteristics of coarse aggregate, fine aggregate, and asphalt (filler).The results of this study indicate that the material from Mount Tambolang Toraja Utara fulfills the requirements set in the 2018 General Highways specification. Based on the composition of the AC-BC mixture using material from Mount Tambolang, namely coarse aggregate 42.82%, fine aggregate 45 , 73%, filler material 5.45%, with an optimum aspaI content of 6%. After doing the Conventional Marshall test, the results obtained, the test meets the specifications on testing flow, stability, VMA, VIM and VFB. While the remaining Marshall stability using material from Mount Tambolang, North Toraja District, meets the requirements of the 2018 General Bina Marga Specifications, namely 96.29%> 90%.

Multi-method approach to assess the corrosion behavior of a coated WE43 Mg alloy

Developing appropriate and functional coatings for Mg-alloys, such as WE43, in view of controlling the degradation rate in biodegradable applications, requires a realistic understanding of the corrosion processes. While conventional methods such as electrochemical measurements can already give a good estimation about the protectiveness of coatings, immersion tests are also required to simulate a more realistic corrosion scenario (i.e., open-circuit dissolution as a function of time). Mass-loss experiments are a well-established method to determine the total corrosion rates at the end of such tests. However, these tests provide a very static result and may be difficult to interpret depending on the dissolution behavior of the coatings. Therefore, we present an analysis of an experimental approach to compare electrochemical data with immersion testing, in which mass loss, hydrogen evolution and ion release data were collected for each sample. Corrosion behavior was studied for bare WE43 alloy as well as for samples with different types of surface pre-treatments and coatings. Critical issues in the different experimental approaches are discussed.

Air-Coupled, Contact, and Immersion Ultrasonic Non-Destructive Testing: Comparison for Bonding Quality Evaluation

The objective of this study is to compare the performance of different ultrasonic non-destructive testing (NDT) techniques for bonding quality evaluation. Aluminium-epoxy-aluminium single lap joints containing debonding in the form of release film inclusions have been investigated using three types of ultrasonic NDT methods: contact testing, immersion testing, and air-coupled testing. Apart from the traditional bulk wave ultrasound, guided wave testing was also performed using air coupled and contact transducers for the excitation of guided waves. Guided wave propagation within adhesive bond was numerically simulated. A wide range of inspection frequencies causing different ultrasonic wavelengths has been investigated. Average errors in defect sizing per ultrasonic wavelength have been used as a feature to determine the performance of each ultrasonic NDT technique. The best performance is observed with bulk wave investigations. Particularly, the higher frequencies (10–50 MHz) in the immersion testing performed significantly better than air-coupled testing (300 kHz); however, air coupled investigations have other advantages as contactless inspection. Whereas guided wave inspections show relatively lower accuracy in defect sizing, they are good enough to detect the presence of the debonding and enable to inspect long range. Even though each technique has its advantages and limitations, guided wave techniques can be practical for the preliminary in-situ inspection of adhesively bonded specimens.

Effects of hydroxyapatite content on mechanical properties and in-vitro corrosion behavior of ZK60/HA composites

In this study, hydroxyapatite-reinforced ZK60 Mg alloybased composites were fabricated via a powder metallurgy route. The mechanical properties of these composites were studied by compressive tests and hardness tests. The in-vitro corrosion behavior was also investigated using immersion testing and electrochemical measurement. The influence of hydroxyapatite content on the mechanical properties and invitro corrosion behavior was evaluated. The microstructure and corrosion morphology were characterized by means of X-ray diffraction, optical and scanning electron microscopy. The results showed that the composite materials with 10 wt.% hydroxyapatite exhibited a better combination of mechanical strength and corrosion resistance. Compared with ZK60 alloy, the addition of 10 wt.% hydroxyapatite resulted in an increase in corrosion resistance by 38.6%.