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By the use of the transmitting–receiving pulse method, the elastic constants and mechanical losses in polycrystalline iron are investigated. The study covers the frequency range from 3 to 10 MHz and extends from room temperature up to 1100°C. The results show three main features: (1) The velocity of longitudinal ultrasonic waves suffers an anomalous depression at the α‐γ transformation temperature. From the magnitude of this depression it is concluded that this transformation is mainly a dilatational process. (2) For an annealed specimen the attenuation–temperature curves show two types of peaks which occur at constant temperatures independently of the ultrasonic frequency used. One type is related to redistribution of spin clusters inside the main domain. The other occurs at the α‐γ phase transformation temperature. (3) In a quenched specimen the attenuation–temperature curves show an attenuation peak which is shifted to higher temperatures with increase of ultrasonic frequency. This peak is accounted for by a temperature‐dependent structure‐relaxational model.

The inhibitory action of Schinus molle L. essential oil was investigated for the corrosion of carbon steel in 1 M hydrochloric acid solution using weight loss, polarization curves, and electrochemical impedance spectroscopy. The inhibition efficiency has increased with the increase of the inhibitor concentration, reaching a value of up to 70% at 2 g/L.

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