The determination of 52 elements in marine geological samples by an inductively coupled plasma optical emission spectrometry and an inductively coupled plasma mass spectrometry with a high-pressure closed digestion method

An improved analytical method to determine the content of 52 major, minor and trace elements in marine geological samples, using a HF-HCl-HNO_3 acid system with a high-pressure closed digestion method（HPCD）, is studied by an inductively coupled plasma optical emission spectrometry（ICP-OES） and an inductively coupled plasma mass spectrometry（ICP-MS）. The operating parameters of the instruments are optimized, and the optimal analytical parameters are determined. The influences of optical spectrum and mass spectrum interferences, digestion methods and acid systems on the analytical results are investigated. The optimal spectral lines and isotopes are chosen, and internal standard element of rhodium is selected to compensate for matrix effects and analytical signals drifting. Compared with the methods of an electric heating plate digestion and a microwave digestion, a high-pressure closed digestion method is optimized with less acid, complete digestion,less damage for digestion process. The marine geological samples are dissolved completely by a HF-HCl-HNO_3 system, the relative error（RE） for the analytical results are all less than 6.0%. The method detection limits are 2–40μg/g by the ICP-OES, and 6–80 ng/g by ICP-MS. The methods are used to determine the marine sediment reference materials（GBW07309, GBW07311, GBW07313）, rock reference materials（GBW07103, GBW07104,GBW07105）, and cobalt-rich crust reference materials（GBW07337, GBW07338, GBW07339）, the obtained analytical results are in agreement with the certified values, and both of the relative standard deviation（RSD） and the relative error（RE） are less than 6.0%. The analytical method meets the requirements for determining 52 elements contents of bulk marine geological samples.

Contribution of T_1 Precipitates to Strength in Two Kinds

The behavior of interaction between dislocation and T 1 plate was observed and analyzed by means of TEM technique in Al Li alloys of 2090 and 2090+Ce. The observation results show that the interaction between dislocation and T 1 plate is a mix type of shearing and Orowan looping, and the physical models are established by theory of precipitates strengthening. The results of calculation illustrate that the contribution of T 1 plate is up 30%～60% to the overall critical resolved shear stress (CRSS). The role of T 1 plate is enhanced with aging time in the material aged 3～48 h at 190℃, but this enhancing effect becomes gentle on overaged condition. The strengthening effects of T 1 plate in 2090 and 2090+Ce alloys are little different on under aged condition, but the strengthening effects of T 1 precipitates in alloy 2090+Ce is little bigger than that of 2090 on overaged condition, especially the cutting mechanism is only considered. The difference between strengthening effects of matrix in two alloys is about 3.2 MPa on underaged condition and 8.7 MPa or so on overaged condition.