Nanosized alloy nitrides or alloying element (M)-Nitrogen(N) cluster formed in plasma nitriding of Fe-M binary alloys were investigated by means of high resolution TEM. Specimen surface of the Fe-Cr alloys was hardened by the formation of disk shaped CrN of NaCl structure, which is ,2 nm thick and 10 nm in diameter. In nitrided Fe-Al specimen, two kinds of AlN nitrides of metastable NaCl type and stable wurtzite type were formed near the specimen surface. Both of these were much larger than CrN. Contrasting to these specimens, in nitrided Fe-Ti and Fe-V alloys, high density M-N clusters of few nanometres diameter, many of which were monolayered lying on {001} a , were formed, leading to larger hardness increase than that in Fe-Cr and Fe-Al alloys. The formation of M-N clusters in nitriding is explained by the thermodynamical analysis of phase separation between M/N poor and M/N rich bcc phases.

Nitriding is one of the most popular heat treatments widely used in hydraulic sliding parts of automotive or construction machinery components. Since the nitrided steels shows great wear resistance due to its high hardness, it is widely applied to various sliding parts in the hydraulic system of construction machinery. During operation, these parts are usually lubricated with fully formulated oils, which include various additives such as dialkyldithiophosphate (ZnDTP), dispersant, detergent, etc. In this study, the tribological features of two kinds of nitrided surfaces lubricated with fully formulated oil and sample oils were evaluated by changing the combination of additive element formulations, and the effect of additive formulation on tribofilm formation and frictional property were investigated in detail. As a result, it was revealed that there is a large interaction between the nitrided surfaces and additives, the coexistence of ZnDTP and detergent affects the phosphorous-derived tribofilm formation on nitrided surface as well as their frictional properties. In particular, the low frictional characteristics of nitrided compound layer was characterized by the smoothed surface and low tribofilm formation on the track.

Eosinophilic myocarditis is a rare subtype of myocarditis characterized by myocardial eosinophilic infiltration, and it is potentially fatal if left untreated. Although endomyocardial biopsy (EMB) is a cornerstone for the histological diagnosis of acute eosinophilic myocarditis (AEM), as it is an invasive procedure and has a low diagnostic accuracy, the diagnosis of AEM with hemodynamic instability remains challenging. We describe a case of AEM presenting as low-flow heart failure with preserved ejection fraction (HFpEF), with rapid progression to cardiogenic shock. The constellation of peripheral eosinophilia, increased left ventricular wall thickness, and HFpEF raised the suspicion of AEM. Contrast-enhanced computed tomography (CT) scan revealed heterogeneous hypoenhancement localized in the basal-to-mid septal and mid anterolateral walls of the left ventricle, strongly suggestive of acute inflammation. Based upon these findings, we performed CT-guided EMB, which lead to a definitive diagnosis. Subsequent high-dose corticosteroids allowed a rapid and dramatic recovery and normalization of cardiac structure and function. This case highlights the clinical importance of assessing AEM as a rare cause of HFpEF and the usefulness of CT-guided EMB in patients with hemodynamic instability.

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