Methods of characterizing aluminum oxides

A method of characterizing aluminum oxide defects in aluminum castings comprising:

• determining a magnesium content in the aluminum oxide defect using a technique selected from the group consisting of energy dispersion spectrum (EDS), X-ray Diffraction, inductively coupled plasma atomic emission spectroscopy (ICP-AES), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, contact-mode atomic force microscopy (AFM), Auger electron spectroscopy (AES), and X-ray Photoelectron spectroscopy (XPS);
• determining a waviness and a roughness of the aluminum oxide defect by topographically measuring a surface of said aluminum oxide defect with a microscope;
• classifying the aluminum oxide defect as an old oxide formed during or prior to melting if the magnesium content is greater than 30 wt %;
• classifying the aluminum oxide defect as an old oxide formed in pouring ladle if the magnesium content is greater than 10 wt % up to 30 wt %;
• classifying the aluminum oxide defect as a type I young oxide—type I fold if the magnesium content is greater than 5 wt % up to 10 wt %, and the waviness is greater than 1 SDAS and less than 1 grain size, and the roughness is less than 1 SDAS;
• classifying the aluminum oxide defect as a type II young oxide—type II fold if the magnesium content is greater than 5 wt % up to 10 wt %, and the waviness is greater than 1 grain size, and the roughness is greater than 1 SDAS;
• classifying the aluminum oxide defect as a type III young oxide—cold-lap if the magnesium content is greater than 1 wt % up to 5 wt %, and the waviness is greater than 1 SDAS and less than 1 grain size, and the roughness is less than 1 SDAS;
• and
• classifying the aluminum oxide defect as type IV young oxide—entrained bifilm if the magnesium content is less than 5 wt %, and the waviness is 1 SDAS or greater, and the roughness is greater than 1 SDAS;
• if said aluminum oxide defect is classified as an old oxide, enhancing filtration between a melting furnace and a casting mold;
• if said aluminum oxide defect is classified as a young oxide, optimizing a location and geometry associated with a gating/riser system into which a liquid melt flows prior to casting.

A method of characterizing aluminum oxide defects in aluminum castings comprising:

• determining a magnesium content in the aluminum oxide defect using energy dispersion spectrum (EDS) with said scanning electron microscope;
• classifying the aluminum oxide defect as an old oxide if the magnesium content is greater than 10 wt %;
• and
• classifying the aluminum oxide defect as a young oxide if the magnesium content is 10 wt % or less;
• if said aluminum oxide defect is old, enhancing filtration between a melting furnace and a casting mold;
• if said aluminum oxide defect is young, optimizing a location and geometry associated with a gating/riser system into which a liquid melt flows prior to casting.