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"Penelitian ini membahas tentang berapa laju pembentukan dan energi aktivasi barium heksaferrite. Telah dilakukan eksperimen pada barium hexaferrite dengan suhu 900℃, 1100℃, dan 1200℃ masing-masing selama 1, 3, 5, 7, dan 10 jam. Diperoleh hasil bahwa pada suhu 900℃ laju pembentukan adalah 6,69x10-4/menit, pada suhu 1100℃ adalah 3,02x10-4 dan suhu 1200oC adalah 1,23x10-4/menit dengan n-1. Sedangkan energi aktivasi barium hexaferrite adalah 83,91 Kj/mol.

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This research study about how much accelerating hexaferrite barium activation energy and forming. Have been done by experiment at hexaferrite barium with temperature 900℃, 1100℃, and 1200℃ each during 1, 3, 5, 7, and 10 hour. Obtained by result of that at temperature 900℃ accelerating forming is 6, 69x10-4 / minute, at temperature 1100℃ is 3, 02x10-4 and temperature 1200oC is 1, 23x10-4 / minute with n-1. While activation energy of hexaferrite barium is 83, 91 Kj / mole."

"The kinetics of isothermal phase transformation in tempered embrittlement stainless stell zeron-25 (SAF-2507): The kinetics study of phase transformation in stainless steel SAF 2507 heat-treated at 800,850 and 900 oC have been done.Eitheir observation of microstructure for treated materials by an optical or electron microscope confirmed the formation of carbide phase at grain boundaries between ferrite and austenite lead to three phase materials.It is furthur observed that for the three treated tempereture there were no significant change in volume fraction of territe phase found and thus it may be be assumed constant..Hovewer,this was not the case for two other phase in wich volume fraction of carbide phase show an increase and followed by a decrease in in volume fraction of austenite phase.It is then concluded that the carbide transformed from austenite.The number of volume fraction of carbide phase determinet by XRD methods were ranged from 6.0%to20% depends on time andtemperature of treatments.An avrami equation for kinetic sudy of phase transformation weresuccessively used for construction of phase transformation curves from which some kineticparameters of phase transformation were succesfully derived,among them the avarage constantrate reaction(n) equals to about one,the activation energy below 850oC is 304 and for 850oC above is 307 kj/mol.With kinetics constans above,the complete IT diagram for iso embrittlement of stainless steel SAF 2507 was succesfully built theoretically."

"Penelitian ini membahas pembentukan besi dari Mill scale secara efesien. Millscale yang terdiri atas 3 jenis fasa dioksidasi dahulu menjadi fasa tunggal hematite. Kemudian hematite dicampur dengan karbon dengan perbandingan berat 1:1 setelah itu dipanaskan menggunakan laju pemanasan 10ºC/menit untuk mencari temperatur efesien untuk proses reduksi oksida besi. Setelah diperoleh temperatur efesien laju pemanasan menuju dan lama pada temperatur efesien divariasikan untuk mendapatkan laju pemanasan yang efesien. Setelah didapatkan temperatur, laju dan lama pemanasan efesien dicari berat carbon minimum untuk proses reduksi. Efektivitas dari proses reduksi berusaha ditingkatkan menggunakan high energy ball mill. Disimpulkan proses reduksi paling efesien menggunakan laju pemanasan 20ºC/menit hingga temperatur 1000ºC dimana temperatur tersebut ditahan selama 1 jam. Sedangkan perbandingan karbon dengan hematite yang paling baik adalah 1:1 lebih besar dari hasil yang diperoleh berdasarkan perhitungan. Sedangkan proses ball mill terbukti mampu meningkatkan efektivitas proses reduksi di udara bebas.

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This research discusses how to make iron from mill scale efficiently. Mill scale which is comprised of three phase is oxidized into a single phase hematite. After that hematite is mixed with carbon with a ratio of 1:1 and then heated with a 10K/menit heating rate to find the efficient temperature for an iron oxide reduction process. After obtaining the efficient temperature the heating rate and time of heating is varied for the efficient temperature this is to obtain the efficient heating rate. After obtaining the efficient temperature, heating rate and time of heating the minimum weight of carbon for the reduction process is searched. The effectivity of the reduction process is increased using high energy ball mill.

The conclusion is that the most efficient process of reduction is using a 20 C/menit heating rate up to 1000ºC where it is held for 1 hour. While the weight ratio between hematite and carbon is 1:1 bigger than the calculated result. And the ball mill process is proven to have increased the effectivity of the reduction process on free air."