Nur Farhana Hayazi
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Preferred name
Nur Farhana Hayazi
Official Name
Nur Farhana, Hayazi
Alternative Name
Hayazi, Nur Farhana
Hayazi, N.F
Nur Farhana Hayazi
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Scopus Author ID
55899042500

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Creep rupture and thermal shock failures of nickel-based alloy reformer tubes a comparative analysis

2024-12 , Nur Farhana Hayazi , Junaidi Che Halim , Ku Adri Azhan Ku Mohamad

This paper examines the failures of radiant tubes within a fertilizer plant's steam reforming unit between the creep rupture and thermal shock, encompassing discussions on the characteristics of the failures, microstructural analysis of the failures, the mechanisms of degradation at high temperatures, and forthcoming preventive actions. The primary reformer is where the initial stage of the steam reforming process occurs, involving the downward passage of a preheated hydrocarbon and steam mixture through radiant tubes containing catalysts. The resulting reformed gas, enriched with carbon monoxide, is further processed into ammonia- rich synthesis gas. These radiant tubes, crafted through centrifugal casting and primarily composed of 35% nickel and 25% chromium, operate at temperatures of 9100C. The discovery of a leaking radiant tube necessitated an unscheduled shutdown, with the failure manifesting as an elliptical window-shaped rupture situated 590 mm from the tube's upper end. The affected tube was subsequently removed, and the outlet weldolet was sealed. During an online refractory repair operation, a catalyst tube exhibited a circumferential crack at a location 770 mm from the tube's upper end. At the same time, another catalyst tube was also observed with a longitudinal crack located at 5130 mm from the tube’s upper end. To address these issues, both tubes were isolated from service through crimping at the top inlet hairpin and bottom outlet pigtail. Detailed metallurgical and failure analyses unveiled that one of the failures was initiated by intergranular cracking at the outer diameter, associated with thermal shock-induced cracking, followed by fatigue-driven crack propagation due to thermal stress and cyclic loading. Meanwhile, the other failed tube identified creep as the failure mechanism due to a combination of time, temperature and stress under such extreme operating conditions. The paper further explores the similarities and differences between these two radiant tube failure incidents and associated failure morphology and mechanisms.

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Mineralogical characterizations of Langkawi ilmenite ore for carbothermal reduction

2022-01-01 , Mohammed A.I. , Nur Farhana Diyana Mohd Yunos , Muhammad Asri Idris , Zul Azhar Zahid Jamal , Nur Farhana Hayazi , Nomura T.

The mineralogical characterizations of Langkawi’s ilmenite were investigated using XRD, XRF and SEM/EDS for morphological analysis. The minerals mainly consisted the phases of FeTiO3, Fe3O4 and TiO2 and Rietveld refinement indicated that the ore contained 35.85% of TiO2 and 26.52% of Fe3O4. The amount of the elements calculated form the quantitative and XRF analysis are reliable and in acceptable ranges. The morphology of the ore showed that the ore is formed mainly in sub-rounded grains with titanium and iron as main elements. The ore was categorized as a low-grade ore, but it can be upgraded for TiO2 production using carbothermal reduction reactions, where the results of XRD, XRF, SEM showed extractable amount of TiO2 more than 32wt%.

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Investigation of corrosion behaviour of mild steel embedded in geopolymer paste with curing and non-curing process

2023 , Fatin Shahira Shaharudin , Farah Farhana Zainal , Nur Farhana Hayazi , Nur Izzati Muhammad Nadzri , Noraziana Parimin , Sri Hastuty , Andri Kusbiantoro

This research was conducted to examine the corrosion behaviour of mild steel bar embedded in geopolymer paste based fly ash Class F during curing and non-curing process. The geopolymer paste was fabricated by blending in the fly ash with alkaline activators (NaOH solution with molarity of 12 M, 2.5 ratio of solution Na2SiO3/NaOH). The paste was produced in 50 mm × 50 mm × 50 mm mould where the mild steel bar of 100 mm (length) × 12 mm (diameter) was embedded at the center of geopolymer paste. This is to comprehend the corrosion behaviour of mild steel embedded in geopolymer paste with and without curing process. Process of curing is carried out for 24 hours at a temperature of 60°C in oven. While on the contrary, the non-curing process will only be leave at room temperature. Both samples were tested after 28 days of curing to determine the corrosion behaviour, phase analysis and morphology analysis. In accordance with the morphology analysis, it shows that the fly ash was totally reacted with alkaline solutions in curing geopolymer paste sample while the non-curing geopolymer paste has shown the unreacted fly ash with high number of pores. The phase analysis of mild steel embedded in this geopolymer paste during curing and without curing process has proven that the presence of new crystallographic peak which also known as passive layer occurred. The potential values result by OCP testing shows the curing sample has highest potential values as compared to the non-curing sample ones.

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Failure analysis on U-bend header tube of boiler economizer

2020 , Nur Farhana Hayazi , Shaiful Rizam Shamsudin , Rajaselan Wardan

A water tube boiler is a type of boiler in which water circulates in tubes heated externally by fire. It was found that the water tube economizers are often subject to the serious damage mainly because of the overheating and corrosion. Thus, the metallurgical investigation procedures starts with the visual inspection, stereomicroscopy, metallography and chemical analysis methods. It was identified that the failure of the u-bend tube was due to the cracking caused by bending forces during the procedures. This cracking causes a leak for the tube. The appearance of corrosion on the shell side is due to the presence of small content of sulphur under the boiler environment. Several welding imperfections were also detected, however, both corrosion and welding imperfections were not the primary caused of the tube failure. From the analysis, the use of SUS304 grade stainless steel was discovered to be the appropriate material selection for the tube boiler.

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Unlocking the metastable phases and mechanisms in the dehydrogenation process of titanium hydride

2020 , Nur Farhana Hayazi , Yu, Wang , Sammy Lap Ip Chan

There are many advantages of using titanium hydride (TiH2) as a starting material for the fabrication of titanium products. However, a thorough understanding of the dehydrogenation process in the fabrication is crucial to ensure the high quality of the Ti components to be produced. In this work the phase transformations sequence during the dehydrogenation of TiH2 powder to titanium have been investigated in detail using thermal analysis, high temperature XRD and Rietveld refinement. With the application of Rietveld refinement, the cell parameters and phase changes have been accurately determined, and the results reveal that the dehydrogenation of TiH2 to Ti consists of several steps and involves a few previously unreported metastable phases and the equilibrium phases. The metastable phases actually possess the same crystal structures as those of the equilibrium phases, but with different lattice parameters. Under some conditions the metastable phases will be retained at ambient temperature. These metastable phases have been confirmed by transmission electron microscopy (TEM) and selected area electron diffraction (SAED). A step-transition mechanism has been proposed to explain the transformation process. This study will be useful for the fabrication of titanium-based composites and titanium alloys from TiH2 powder.

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Analysis of process parameters for resistance spot welding on galvanized steel using taguchi method

2025 , Nur Farhana Hayazi , P. Jaraman , Dewi Suriyani Che Halin , F.M. Foudzi , M. Nabiałek , P. Vizureanu

Resistance spot welding (RSW) involved two or more sheets of metal that are welded together with or without filler mate­rials. This paper discussed the optimization of RSW process parameters that were varied on galvanized steel below 6 kA by using Taguchi method. Galvanized steel can be more difficult to spot weld than any other uncoated metal due to the tendency of zinc coating alloying with electrodes. The three process parameters are welding current, welding time and holding time. The type of OA used in this study was L9. Subsequently, tensile and Vickers microhardness tests were conducted on the sample. Results from these tests were used to calculate the S/N ratio, ANOVA and confirmation test. The optimal parameters value and percentage of contributing factors to the welding can be identified. It will help to produce high-quality weld joints.

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Incoloy 800HT weldolet integrity in hot collector replica testing insights

2024-12 , Nur Farhana Hayazi , Ku Adri Azhan Ku Mohamad , Junaidi Che Halim , Shaiful Rizam Shamsudin

In this paper, the integrity assessment of Primary Reformer’s hot collector weldolet in the fertilizer plant was conducted. It aims to discuss the findings of the relevant weldolet weldments which include dye penetrant test ultrasonic test, in-situ field metallography (replication), hardness measurements and rectification measures. The first step of the steam reforming process takes place in the Primary Reformer, where preheated hydrocarbon and steam mixture is passed downwards through vertical tubes containing catalyst. The hot gas that exited from the catalyst tubes is termed reformed gas and will enter two headers, namely hot and cold collectors. From then, the reformed gas will transform into raw ammonia synthesis gas after undergoing several processes. The facility was commissioned in 2006 and is still in operation. During the Plant Turnaround in 2022, the Primary Reformer’s hot collector weldolet component is categorised as high nickel content material, commercially known as Incoloy 800HT, was detected with circumferential crack at several locations. The operating temperature of the weldolet is 8110C. The observed damage mechanism of the crack was “Aged Phenomenon”. However, at four locations of the weldments, further dye penetrant test (DPT) and metallurgical testing using replica test had observed sigma phase microstructure which is related to sigma phase embrittlement (SPE) without any creep cavity observed. Finally, both occurrences were reported and reviewed.

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Mineralogical characterizations of Langkawi Ilmenite ore for carbothermal reduction

2022-01 , A. I. Mohammed , Nur Farhana Diyana Mohd Yunos , Muhammad Asri Idris , Zul Azhar Zahid Jamal , Nur Farhana Hayazi , T. Nomura

The mineralogical characterizations of Langkawi’s ilmenite were investigated using XRD, XRF and SEM/EDS for morphological analysis. The minerals mainly consist of the phases of FeTiO3, Fe3O4 and TiO2 by Rietveld refinement, which indicated that the ore contains 35.85% of TiO2 and 26.52% of Fe3O4. The amount of the elements calculated from the quantitative and XRF analysis are reliable and in acceptable ranges. The morphology of the ore shows that the ore is formed mainly in sub-rounded grains with titanium and iron as the main elements. The ore is categorized as a low-grade ore, but it can be upgraded for TiO2 production using carbothermal reduction reactions, where the results of XRD, XRF, SEM showed an extractable amount of TiO2 more than 32wt%.

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Influence of sodium chloride on recycled HDPE in superhydrophobic surface development

2024-12 , Thor Keat Seng , Muhammad Salihin Zakaria , Razif Muhammed Nordin , Khairul Anwar Abdul Halim , Nur Farhana Hayazi , Lokman Hakim Ibrahim

Inspired by lotus leaf, superhydrophobic surfaces have emerged rapidly in recent years. It is due to its excellence ability in self-cleaning and corrosion protection, to name a few. In this research, a green superhydrophobic surface was constructed on the surface of recycled High-Density Polyethylene (rHDPE) by utilizing Sodium chloride (NaCl) as a water-soluble surface modifying agent. The treatment process is simple,and cost-efficient as it only used rHDPE and NaCl as the main materials with additional chemicals and at the same time leave no impact on the environment. Variation of NaCl grinding period influenced the value of CA by which 240 minutes grinded NaCl displayed highest CA of 161.4°. This may be attributed by the increase of surface roughness as the grinding time increase. Furthermore, the surface morphology, topography, and self-cleaning ability of superhydrophobic surafce were analyzed to further understand the surface characteristics. The anti-sticking and self-cleaning properties were successfully displayed by the superhydrophobic surface thus, showing its potential as an eco-friendly material.

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Short review: biowaste as a source of silica and Its application as a filler to fabricate the superhydrophobic silica-based coating

2024-03 , Nur Fatihah Mohd Fadzil , Muhammad Salihin Zakaria , Khairul Anwar Abdul Halim , Nur Farhana Hayazi , Lokman Hakim Ibrahim , Razif Muhammed Nordin

Silica (SiO2) plays a major key ingredient in producing products such as toothpaste, ceramics, and paints, to name a few, as it acts as a stabilizing agent, filler and additive. Due to its excellent properties, the use of high-purity SiO2 in industrial applications is favourable. Unfortunately, high-purity SiO2 is expensive. Tetraethyl Orthosilicate (TEOS) is an example of a SiO2 precursor that is costly and harmful, yet frequently employed. This paper provides a short review of the advantages of biowaste materials as SiO2 precursors and their role as fillers in the fabrication of superhydrophobic coating. Researchers nowadays are attempting to lower the expense of employing high-purity SiO2 by extracting silica from biowaste using many methods such as acid leaching and alkali treatment as this option is highly sustainable. The growth of agricultural industries is exponential due to the increase in biowaste production. Therefore, this is one of the ways to utilize the use of biowaste in combatting the environmental issues regarding excess biowaste and receding pure resources. SiO2 from biowaste also can be utilized as filler and used to develop superhydrophobic coating, providing numerous potential applications.

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