High-entropy alloys (HEA) have emerged as promising structural materials for use in extreme environments where conventional alloys face limitations. In this study, ferritic Fe-Al-Cr-Ni-Ti alloys were developed by employing the HEA design concept to promote coherent L21 precipitation within a BCC matrix. The systematic variation of Al content enhanced lattice coherency, precipitation strengthening, and the rapid formation of protective Al2O3 scales. The alloy with 16 at% Al exhibited superior high-temperature mechanical performance, showing a yield strength of approximately 400 MPa and ~5 % uniform elongation at 700 °C, exceeding the use temperature limit of conventional steels. Steam oxidation tests demonstrated the formation of dense, continuous alumina films, while hot rolling and grain refinement effectively improved room-temperature ductility. These findings indicate that Fe-Al-Cr-Ni-Ti alloys offer a cost-effective pathway to achieve a balanced combination of heat resistance, corrosion resistance, and mechanical processability, suggesting their potential as strong candidates for next-generation energy and high-temperature structural applications.

In additive manufacturing, the flowability of feedstock particles determines the quality of the parts that are affected by different parameters, including the chemistry and morphology of the powders and particle size distribution. In this study, the microstructures and flowabilities of gas-atomized heat-resistant alloys for additive manufacturing applications are investigated. A KHR45A alloy powder with a composition of Fe-30Cr-40Mn-1.8Nb (wt.%) is fabricated using gas atomization process. The microstructure and effect of powder chemistry and morphology on the flow behavior are investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and revolution powder analysis. The results reveal the formation of spherical particles composed of single-phase FCC dendritic structures after gas atomization. SEM observations show variations in the microstructures of the powder particles with different size distributions. Elemental distribution maps, line scans, and high-resolution XPS results indicate the presence of a Si-rich oxide accompanied by Fe, Cr, and Nb metal oxides in the outer layer of the powders. The flowability behavior is found to be induced by the particle size distribution, which can be attributed to the interparticle interactions and friction of particles with different sizes.

습식제련 공정 침출액은 다양한 유가금속 및 희소금속을 함유하고 있지만, 회수기술 부족으로 중화, 치환, 흡착을 통해 폐기되고 있다. 폐산 용액에 존재하는 금속들을 경제적으로 회수하기 위해 막분리 공정 개발의 필요성이 강조되고 있으며, 본 연구에서는 내산/내열성이 우수한 나노복합막을 제조하고자 하였다. 나노복합막은 polysulfone(PSf) 위에 지방족 아민과 아실클로라이드(acyl chloride) 를 계면중합하여 제조하였다. 내산성 평가는 15 wt% 황산 용액에 일별 노출한 후 75psi 압력 하에서 cross-flow 방식으로 투과수량 및 이온 제거율을 측정하 였다. 내열성 평가는 운전 온도 60°C에서 투과평가를 진행하였다. 제조막의 특 성은 FTIR, XPS, FE-SEM 등의 분석 통해 확인하였다.

전기⋅전자산업이 급격하게 발전함에 따라 유가금속 및 희소금속의 수요가 급증하고 있다. 유가금속들은 주로 제련산업 공정에서 다량 방출되며, 회수기술 부족으로 중화, 치환, 흡착을 통해 폐기되어 큰 비용으로 경제적이지 못하다. 이에 분리막을 통한 유가금속회수 소재개발의 필요성이 강조되고 있다. 유가금속이 포함된 습식제련 공정 침출액(15% 황산 용액, 온도 60°C)은 다량의 다가이온과 1가이온을 포함하고 있기 때문에 이온별 분리가 가능해야 하며, 특히 구리와 같은 2가 유가금속 분리성능이 우수해야 한다. 또한, 지속적인 분리/농축을 위해 산에 대한 안정성이 중요하다. 따라서 본 연구를 통해 2가 금속 배제율 98%, 유량 33GFD 성능을 1개월 이상 유지하는 나노분리막 제조 연구 개발을 수행하고 있다.

Inorganic oxide colloids dispersed in alcohol were applied to a stainless steel substrate to produce oxide coatings for the purpose of minimizing emissive thermal transfer. The microstructure, roughness, infrared emissive energy, and surface heat loss of the coated substrate were observed with a variation of the nano oxide sol and coating method. It was found that the indium tin oxide, antimony tin oxide, magnesium oxide, silica, titania sol coatings may reduce surface heat loss of the stainless steel at 300˚C. It was possible to suppress thermal oxidation of the substrate with the oxide sol coatings during an accelerated thermal durability test at 600˚C. The silica sol coating was most effective to suppress thermal oxidation at 600˚C, so that it is useful to prevent the increase of radiative surface heat loss as a heating element. Therefore, the inorganic oxide sol coatings may be applied to improve energy efficiency of the substrate as the heating element.

The new alloy1) is made from rapidly solidified Al-Ni-Zr-Ce aluminum alloy powder, and has the following unique mechanical characteristics:(1) The stress-strain curve shows a yield point; (2) The alloy shows high heat resistance; (3) Although the alloy is submicron particle diameter, it shows excellent creep resistance. We observed the micro structures of this new alloy, and it is thought that is based on the following reasons:(1) The dislocation strongly adheres to the alloy’s many crystal boundaries;(2) The added alloying elements have a small diffusion coefficient in aluminum;(3) The tiny intermetallic compound particles crystallizing at the grain boundary.

Background : Stable ginseng production is highly dependent on specific climate conditions. Recently, ginseng yield and quality are negatively affected by climate changes, particularly global warming. Thus, it is imperative to apply a new systematic cultivation method and to develop new varieties with enhanced heat resistance to cope with elevated temperatures. Up to date, ginseng breeding program has mainly focused on the quantity and process ability of red ginseng. New varieties with increased resistance to diverse abiotic stresses need to be developed. Methods and Results : In this study, 13 varieties and 100 germplasms were screened for resistance to heat stress. To measure heat resistance, seedlings were transplanted to a pot 3 times in threes. Two months later, the pot was placed in a temperature chamber at 46℃ for 1 hour, a critical condition that ginseng appears to stop cellular respiration. After waiting for 1 day, the pot was examined for survival rate and fluorescent reaction. Fluorescent reaction was tested according to Nedbal et al. (2000) and Park et al. (2010) and with an image fluorometer. After testing chlorophyll fluorescent reaction, Fm/Fo, Fv/Fm and Rfd were used as screening indices for high temperature resistance. It was found that the adequate values for Fm/Fo, Fv/Fm and Rfd were over 2.2, over 0.55 and over 0.8, respectively. Also, the degree of the above-ground damage is investigated in the 4-year old field. Under our heat stress conditions, susceptible varieties (Chunpoong) and germplasm lines showed drooping and wilting leaf phenotypes, whereas the leaves of a resistant line (named Eumseong 11) remained healthy. Eumseong 11 had the highest values with 2.3, 0.61 and 0.98 in fluorescent test. In addition, compared to the susceptible lines which were wilted in 4-year old field, no detrimental phenotypes were observed in Eumseong 11. Conclusion : ‘Eumseong11’ was selected as a superior line with increased resistance to heat stress. We are now testing how Eumseong11 responds to other abiotic stresses. Our effort will contribute to increase the farmers' income.

High temperature is one of major environmental stress. Heat tolerance managing is difficult through the phenotypic selection, so marker assistant selection (MAS) using molecular markers like as RAPD, SSR etc. was tried to select useful traits for heat tolerance. Fourteen SSR markers reported by previous research were selected for this research. We tried to evaluate 14 SSR markers for MAS using 31 useful wheat resources including 24 crossing line from Turkey, six Korean wheat cultivars and Chinese spring. The average of the number of alleles and PIC values in this study were 6.14 and 0.64, respectively. Two major clades and four sub clades were grouped by phylogenetic tree using UPGMA. Four Korean wheat cultivars were distinct from other Turkey resources in the phylogenetic dendrogram. From the results, we expected that these markers were able to adapt to screening wheat genotyping for heat tolerance.